Methods for detection of cardiac rhythm disorders using basket style cardiac mapping catheter

ABSTRACT

A method for sensing multiple local electric voltages from endocardial surface of a heart, includes: providing a system for sensing multiple local electric voltages from endocardial surface of a heart, including: a first elongate tubular member having a lumen, a proximal end and a distal end; a basket assembly including: a plurality of flexible splines for guiding a plurality of exposed electrodes, the splines having proximal portions, distal portions and medial portions therein between, wherein the electrodes are substantially flat electrodes and are substantially unidirectionally oriented towards a direction outside of the basket.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/148,845, filed Jan. 7, 2014, which is a continuation of U.S.application Ser. No. 13/409,595, filed Mar. 1, 2012, now U.S. Pat. No.8,644,902, which claims the benefit of U.S. Provisional Application No.61/555,190, filed Nov. 3, 2011, and U.S. Provisional Application No.61/478,340, filed Apr. 22, 2011, the contents of all of which areincorporated by reference herein.

FIELD OF THE INVENTION

The present invention is related to methods for the detection of cardiacrhythm disorders by use of basket style cardiac mapping catheters. Thepresent invention is further related to a method for sensing multiplelocal electric voltages from endocardial surface of a heart by using abasket with substantially flat and unidirectionally oriented electrodeson the basket.

BACKGROUND OF THE INVENTION

Heart rhythm disorders are very common in the United States, and aresignificant causes of morbidity, lost days from work, and death. Heartrhythm disorders exist in many forms, of which the most complex anddifficult to treat are atrial fibrillation (AF), ventricular tachycardia(VT) and ventricular fibrillation (VF). Other rhythms may be easier totreat, but may also be clinically significant including supraventriculartachycardia (SVT), atrial tachycardia (AT), atrial flutter (AFL),premature atrial complexes/beats (PAC, APC) and premature ventricularcomplexes/beats (PVC). Under certain conditions, rapid activation of thenormal sinus node can even cause a heart rhythm disorder such asinappropriate sinus tachycardia or sinus node reentry.

Definitive diagnosis has often been performed using electrode-bearingcatheters placed within the heart chambers. Electrodes have beenpositioned along a catheter shaft or basket splines in an attempt toanalyze or map the electrical activity within a heart chamber. Mappingtypically involves the use or formation external (patches on skin) ofelectrograms and internal (catheters with electrodes) electrograms. Atypical electrocardiogram of the cardiac cycle (heartbeat) consists of aP wave, a QRS complex and a T wave. During normal atrial depolarization,the main electrical vector is directed from the SA node, and spreadsfrom the right atrium to the left atrium. Atrial depolarization isrepresented by the P wave on the electrocardiogram. The QRS complexreflects the rapid depolarization of the right and left ventricles. TheT wave represents the repolarization (or recovery) of the ventricles.

Devices of the prior art, however, often do not provide a complete andstable map of the electrical activity within a heart chamber (recordingelectrograms). In particular, electrical activity in certain portions ofthe right atrium and the left atrium (e.g. atrial septum, region ofright pulmonary veins) are often difficult to map because of theinability of devices of the prior art to adequately conform to theirregular shape of the atria and their varying shapes during beating ofthe heart. Further, devices of the prior art do not providedimensionally and/or spatially stable and complete electrograms as theprior art devices often move as the heart beats, thereby moving some orall of the electrodes away from the heart tissue and making the relativeposition of the electrodes variable to corresponding position of atrialtissue.

Thus, there is a need in the art for a cardiac mapping catheter that iscapable of providing improved and dimensionally and/or spatially stablesignals for diagnosis, and more complete coverage of the heart tissue,typically in the form of electrograms.

SUMMARY OF THE INVENTION

The present invention provides devices, systems and methods for thedetection of cardiac rhythm disorders by use of a percutaneous catheterdesigned to permit acquisition of numerous, simultaneous endocardialelectrograms from a three dimensional array of surface electrodes,herein referred to as “a basket style cardiac mapping catheter.”

In one embodiment of the present invention, a method for sensingmultiple local electric voltages from endocardial surface of a heart,includes: providing a system for sensing multiple local electricvoltages from endocardial surface of a heart, including: a firstelongate tubular member having a lumen, a proximal end and a distal end;a basket assembly including: a plurality of flexible splines for guidinga plurality of exposed electrodes, the splines having proximal portions,distal portions and medial portions therein between, wherein theelectrodes are substantially flat electrodes and are substantiallyunidirectionally oriented towards a direction outside of the basket; aproximal anchor for securably affixing the proximal portions of thesplines; the proximal anchor being secured at the distal end of thefirst elongate tubular member; a distal tip for securably affixing thedistal portions of the splines, the proximal anchor and the distal tipdefining a longitudinal axis therein between about which the splines aredisposed; wherein the splines approach the distal tip at an angle ofabout 90° or less than about 90° as measured from a line segment betweenthe proximal anchor and the distal tip along the longitudinal axis;wherein the splines comprise a superelastic material such that thebasket assembly exhibits a substantially cylindrical shape when radiallycompressed and exhibits a radially expanded non-spherical shape when notradially compressed; and wherein each of the splines in the radiallyexpanded non-spherical shape contain a proximal recurve in the proximateportion of the spline at a location near to the proximal anchor of thebasket assembly, the proximal recurve includes a proximal excurvateoutward bend and a proximal incurvate inward bend between the proximalexcurvate outward bend and the proximal anchor, where an apex of theproximal incurvate inward bend is disposed in a direction toward thedistal tip and is further disposed inwardly closer toward the distal tipthan the proximal excurvate outward bend; delivering the system to theheart so that the basket assembly is disposed within the right atrium ofthe heart; contacting proximal atrial tissue with the electrodesdisposed on the proximal spline portions to detect multiple localelectric voltages from endocardial surface thereat; and contactingatrial tissue with the electrodes disposed on the medial spline portionsand the distal spline portions to detect multiple local electricvoltages from endocardial surface thereat.

Desirably, the splines of the basket assembly are flexible to match thecontours of the right atrium, and substantially all of the electrodescontact atrial tissue.

Further, substantially all of the electrodes may remain substantiallyspatially fixed with respect to atrial tissue.

Moreover, a substantial portion of atrial signals detected by the systemhave larger amplitudes than ventricular signals detected by the system.

These and other features and advantages of the present invention willbecome apparent from the following detailed description of illustrativeembodiments thereof, which is to be read in connection with theaccompanying drawings. Corresponding reference element numbers orcharacters indicate corresponding parts throughout the several views ofthe drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the basket style cardiac mappingcatheter system of the present invention.

FIG. 2 is a side elevational view of the basket style cardiac mappingcatheter system of FIG. 1, according to the present invention.

FIG. 3 is a schematic view of an introducing catheter of the prior artuseful for delivery of the basket style cardiac mapping catheter of FIG.1 and guide catheter of FIG. 4 into a bodily lumen or organ.

FIG. 4 is a schematic view of a guide catheter of the prior art usefulfor delivery of the basket style cardiac mapping catheter of FIG. 1 intoa bodily lumen or organ.

FIG. 5 is an expanded, partial cross-sectional view of a portion of thebasket of the system of FIG. 1 showing an expanded basket beyond andoutside a hemostat penetrator and/or a guide catheter, according to thepresent invention.

FIG. 6 is an expanded, partial cross-sectional view of a portion of thebasket of the system of FIG. 1 showing a radially compressed basketwithin a hemostat penetrator and/or a guide catheter, according to thepresent invention.

FIG. 7 is an expanded side view of a portion of the basket of the systemof FIG. 1 showing M-shaped, symmetric distal splines, according to thepresent invention.

FIG. 8 is a perspective view of the M-shaped basket embodiment of FIG.7, according to the present invention.

FIG. 9 is a right side view of the M-shaped basket embodiment of FIG. 7depicting symmetric spline angles, according to the present invention.

FIG. 10 is a perspective view of the basket of the system of FIG. 1showing M-shaped, non-symmetric distal splines according to a basketembodiment of the present invention.

FIG. 11 is a right side view of the M-shaped basket embodiment of FIG.10 depicting non-symmetric spline angles, according to the presentinvention.

FIG. 12 a side elevational view of one of the splines of the M-shapedbasket of FIG. 7 showing proximal spline recurves, according to thepresent invention.

FIG. 13 is a perspective view of the spline of FIG. 12, according to thepresent invention.

FIG. 14 is an exploded side view of a distal portion of the spline ofFIG. 12, according to the present invention.

FIG. 15 is an exploded side view of a proximal portion of the spline ofFIG. 12, according to the present invention.

FIG. 16 is an exploded right side view of a portion of the distalportion of the spline of FIG. 12 showing a distal thinned portion,according to the present invention.

FIG. 17 is an expanded side view of another embodiment of a basket ofthe system of FIG. 1 showing M-shaped distal spline portion and proximaltangential spline curves, according to the present invention.

FIG. 18 is an expanded side view of another embodiment of a basket ofthe system of FIG. 1 showing a distal spline D-shaped curve and proximalrecurves, according to the present invention.

FIG. 19 is a perspective view of the spline of FIG. 18, according to thepresent invention.

FIG. 20 is an exploded view of a distal portion of the spline of FIG.18, according to the present invention.

FIG. 21 is an expanded side view of another embodiment of a basket ofthe system of FIG. 1 showing a distal spline D-shaped curve and proximaltangential spline curves, according to the present invention.

FIGS. 22A through 22D depict thinned side view spline portions,according to the present invention.

FIG. 23A depicts side view of a portion of a spline in a neutralposition having buckle points, according to the present invention.

FIG. 23B depicts side view of a portion of a spline in a deflectedposition having buckle points, according to the present invention.

FIG. 24 is a schematic illustration of a spline emerging from a distaltip at an acute angle, according to the present invention.

FIG. 25 is a schematic illustration of a spline emerging from a distaltip at a substantially perpendicular angle, according to the presentinvention.

FIG. 26A is a front perspective view of a two-part, welded distal tip,according to the present invention.

FIG. 26B is a rear perspective view of the distal tip of FIG. 26A,according to the present invention.

FIG. 26C is a front perspective view of a top part of the distal tip ofFIG. 26A, according to the present invention.

FIG. 26D is a bottom view of the top part of the distal tip of FIG. 26A,according to the present invention.

FIG. 26E is a front perspective view of a bottom top part of the distaltip of FIG. 26A, according to the present invention.

FIG. 26F is a front perspective view of another embodiment of atwo-part, welded distal tip having a rounded or domed upper portion,according to the present invention.

FIG. 27A is a front perspective view of an encapsulated, filament wounddistal tip, according to the present invention.

FIG. 27B is a side elevation view of the distal tip of FIG. 27A,according to the present invention.

FIG. 27C is a rear perspective view of the distal tip of FIG. 27A,according to the present invention.

FIG. 27D is a top perspective view of the filament wrapping of thedistal tip of FIG. 27A, according to the present invention.

FIG. 27E is a rear perspective view of the filament wrapping of thedistal tip of FIG. 27A, according to the present invention.

FIG. 28A is a side cross-sectional view of another embodiment of atwo-part distal tip with half splines, according to the presentinvention.

FIG. 28B is a side cross-sectional view of another embodiment of atwo-part distal tip with half splines, according to the presentinvention.

FIG. 28C is a side cross-sectional view of another embodiment of atwo-part riveted distal tip with full splines, according to the presentinvention.

FIG. 28D is a top view of aligned splines useful with the distal tip ofFIG. 28C, according to the present invention.

FIG. 29 is a side elevational view of an encapsulated distal tip,according to the present invention.

FIG. 30A is a top view of a membrane distal tip, according to thepresent invention.

FIG. 30B is a partial cross-sectional view of the membrane tip of FIG.30A.

FIG. 31A is a perspective view of a slotted proximal anchor, accordingto the present invention.

FIG. 31B is a right cross-sectional view of the slotted anchor of FIG.31A, according to the present invention.

FIG. 31C is an exploded, partial side elevation view of the slottedanchor of FIG. 31A, according to the present invention.

FIG. 31D is a partial cross-sectional view of the slotted anchor of FIG.31A securable disposed with a portion of the catheter body of the systemof FIG. 1, according to the present invention.

FIG. 32A is a depiction of a proximal portion of a spline having aspline notch, according to the present invention.

FIG. 32B is a schematic illustration of an anchor useful for securingthe spline of FIG. 32A, according to the preset invention.

FIG. 32C is a partial exploded view of the anchor of FIG. 32B accordingto the preset invention.

FIG. 33A is an exploded, perspective of the basket of the system of FIG.1 showing splines with spline tube assemblies, according to the presentinvention.

FIG. 33B is a side elevational view of the basket of FIG. 33A, accordingto the present invention.

FIGS. 34A and 34B are cross-sectional views of a portion of the splinetube assembly of FIG. 33A, according to the present invention.

FIG. 34C is an exploded cross-section view of the spline of FIGS. 34Aand 34B, according to the present invention.

FIG. 34D is a cross-sectional view of a spline tube assembly with aradiopaque marker, according to the present invention.

FIG. 34E is a cross-sectional view of the radiopaque marker of FIG. 34D,according to the present invention.

FIG. 34F is a partial cross-sectional view of a spline tube assemblyalong the length of the spline tube assembly with a radiopaque marker,according to the present invention.

FIG. 34G is a representation of a fluoroscopic image of a side elevationview of a basket with radiopaque marker arrangement to depict spline andelectrode locations, according to the present invention.

FIG. 34H is a representation of a fluoroscopic image of a perspectiveview of the basket of FIG. 34G, according to the present invention.

FIG. 34I is a representation of a fluoroscopic image of a rotated sideview of the basket of FIG. 34G, according to the present invention.

FIG. 35A is a perspective view of spline tube assembly, according to thepresent invention.

FIG. 35B is another perspective views of spline tube assembly, accordingto the present invention.

FIG. 35C is an exploded perspective view of a spline tube assembly,according to the present invention.

FIG. 35D is an exploded, partial cross-sectional view of a proximalportion of the spline tube assembly, according to the present invention.

FIG. 35E is an exploded, partial cross-sectional view of a distalportion of the spline tube assembly, according to the present invention.

FIG. 35F is an exploded, partial cross-sectional view of a proximalportion of the spline tube assembly showing two flex circuits embeddedwith a wall of the spline tube assembly, according to the presentinvention.

FIG. 35G is an exploded, partial cross-sectional view of a proximalportion of the spline tube assembly showing one flex circuit embeddedwith a wall of the spline tube assembly, according to the presentinvention.

FIG. 35H is an exploded, partial cross-sectional view of a portion ofthe spline tube assembly showing a flex circuit transitioning into aninner lumen of the spline tube assembly, according to the presentinvention.

FIG. 36A is a top view of a flex circuit, according to the presentinvention.

FIG. 36B is a bottom view of the flex circuit of FIG. 36A, according tothe present invention.

FIG. 36C is an exploded, right bottom view of a portion of the flexcircuit of FIG. 36A, according to the present invention.

FIG. 36D is an exploded, left top view of a portion of the flex circuitof FIG. 36A, according to the present invention.

FIG. 36E is an exploded, left bottom view of a portion of the flexcircuit of FIG. 36A, according to the present invention.

FIG. 36F is schematic, cross-sectional view of a portion of the flexcircuit of FIG. 36A, according to the present invention.

FIG. 37A is a top view of another embodiment of a flex circuit,according to the present invention.

FIG. 37B is an exploded, right top view of a portion of the flex circuitof FIG. 37A, according to the present invention.

FIG. 37C is an exploded, right bottom view of a portion of the flexcircuit of FIG. 37A, according to the present invention.

FIG. 38A is a perspective view of a flex circuit embedded or pressedinto a substrate, according to the present invention.

FIG. 38B is a partial, side cross-sectional view of the flex circuit ofFIG. 38A, according to the present invention.

FIG. 39 is a top view of another embodiment of a flex circuit, accordingto the present invention.

FIG. 40A is a partial perspective view of a quad wire assembly with aflex circuit, according to the present invention.

FIG. 40B is a partial cross-sectional view of the quad wire assemblywith a flex circuit of FIG. 40A, according to the present invention.

FIG. 41A is a partial cut-away perspective view of a catheter shaft witha braided shield and anti-kink beading, according to the presentinvention.

FIG. 41B is a partial cut-away perspective view of another embodiment ofa catheter shaft with a braided shield and anti-kink beading, accordingto the present invention.

FIG. 42A is a side elevational view of asymmetric catheter basket FIG.13, according to the present invention.

FIG. 42B is a front elevational view of a symmetric basket, according tothe present invention.

FIG. 42C is a front elevational view of an asymmetric basket, accordingto the present invention.

FIG. 43A is an electrogram obtained with the catheter basket system ofthe present invention.

FIG. 43B is an electrogram obtained with a catheter basket system of theprior art.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a perspective view of basket style cardiac mapping system orassembly 10 of the present invention, and FIG. 2 is a side elevationview of the catheter system or assembly 10 of FIG. 1. As depicted inFIGS. 1 and 2, the catheter system or assembly 10 consists of threesubassemblies: the mapping catheter assembly 8, including hemostatpenetrator assembly 25, and the extension cable assembly 31. The mappingcatheter assembly 8 includes a spline basket 12, which includes splines14 with spline tube assemblies (not shown) having electrodes (notshown); a catheter body or shaft 20; a hemostat penetrator assembly 25(comprised of a hemostat penetrator tube 22 and hemostat penetratorhandles 24); a handle strain relief 26; a handle 28, with an integralconnector (not shown). The extension cable assembly 31 includes a matingconnector 30 and an extension cable 32; interrelated as shown. Thecatheter assembly 8 allows ease of operation and precise positioning andcontrol of the basket 12 within a patient. Desirably, connector 30 isround so there is no rotational bias as the basket 12 is disposed withina patient. A non-round connector grip, for example a rectangularconnector grip (not shown) may provide a rotational bias which, ifdesired, may be used with the present invention. The mating connectorcable assembly 31 is useful for connecting the catheter assembly 8 toexternal devices (not shown), such as devices that receive and analyzeelectrical signals from the catheter system 10. The strain reliefsection 26 is useful in providing kink resistance to the catheter body20 especially when the catheter assembly 8 is disposed within a patient.

The splines 14 of the spline basket 12 are secured by a distal tip 16 atone end, i.e. the distal end, of the basket 12, and are further securedby a proximal anchor 18 at an opposed end, i.e. the proximal end, of thebasket 12. The anchor 18 is secured to a distal end 20B of the catheterbody 20 and/or within a lumen 20C of the catheter body 20 of thecatheter 8 of the present invention. The proximal end 20A of thecatheter body 20 is secured to the strain relief section 26 of thehandle 28.

The spline basket 12 is deliverable through and into bodily organs, suchas but not limited to the right atrium of a heart. One useful deliverytechnique includes the Seldinger delivery technique. The Seldingertechniques uses a short introducing catheter, such as the introducingcatheter 34 as depicted in FIG. 3, and a longer catheter, such as thecatheter 46, which may also be referred to as an guide catheter ordelivery sheath when described with the system 10 of the presentinvention, as depicted in FIG. 4. The introducing catheter or introducer34 is typically fairly short at about six inches in length and is usedto navigate through muscle and into a desired vein. The catheter 46 istypically a long guide sheath, typically 60 mm to 80 long. In a typicalSeldinger technique, a vessel or cavity is punctured with a sharp hollowneedle or trocar (not shown). If desired, a guidewire (not shown) may bethen advanced through the lumen of the trocar, and the trocar iswithdrawn. The introducing catheter 34 may then be passed over theguidewire into the cavity or vessel. The introducing catheter 34includes a hollow introducer lumen 36. The distal end 42 of theintroducing catheter 34 is positioned with a vessel or cavity. Theproximal end 44 of the introducing catheter 34 remains outside of thepatient so as to allow a practitioner to control the position of thedistal end of the introducing catheter 42. The proximal end 44 of theintroducing catheter 34 may include a hemostat valve 38 and a salineflush lumen 40. The catheter lumen 48 of the guide catheter 46 isdeliverable through the lumen 36 of the introducing catheter 34 to adesired bodily site. The guide catheter 46 includes a distal end 54 anda proximal end 56. The guide catheter 46 may also include a proximalhemostat valve 50 and a saline flush lumen 52.

As used herein the term “proximal” generally refers to a location ordirection towards the practitioner. The term “distal” generally refersto a location or direction away from the practitioner. Further, theterms inner, inward and the like generally refer to a direction towardthe inside of the basket 12, for example towards a longitudinal axis Lbetween the distal tip 16 and the proximal anchor 18. The terms outer,outward and the like generally refer to a direction away from the insideof the basket 12, for example away from a longitudinal axis L betweenthe distal tip 16 and the proximal anchor 18.

In preparation for insertion of the basket catheter 8, the basket 12 iscollapsed within the hemostat penetrator tube 22 of the hemostatpenetrator assembly 25. The distal end 23 of the hemostat penetrator isinsertable through the hemostat valve 50 of the Guide catheter 46. Thebasket 12 and a portion of the catheter body 20 are advanced anddeliverable through lumen 48 and past the distal end 54 of the catheter46. Typically, the strain relief portion 26, the handle 28, the matingconnector 30 and the connector 32 of the system 10 of the presentinvention remain outside of the body or proximally past the proximal end56 of the catheter 46. Upon withdrawal of the hemostat penetrator tube22 from the guide sheath hemostat valve 50, the guide sheath hemostatvalve with create a leak-proof seal against the outer wall of thecatheter body 20, preventing the loss of blood through the introducersystem.

FIGS. 5 and 6 depict an embodiment of the distal end of the basket stylecardiac mapping catheter 8 of the present invention. As depicted in FIG.5 the spline basket 12 is deliverable through and past the distal end 54of the lumen 48 of the catheter 46 and deliverable through and past thedistal end 23 of the hemostat penetrator 25, which also has an openlumen. The distal end 23 of the hemostat penetrator 25 is useful forpenetrating the hemostat valve 56 on the proximal end of the guidecatheter 46.

As depicted in FIG. 5, the splines 14 of the spline basket 12 are in anexpanded state, such as a radially expanded state. The overall shape ofthe expanded basket 14 is depicted as being an expanded, non-cylindricalshape. While the expanded splines 14 are depicted in a spherical orsomewhat spherical orientation, the present invention is not so limited.Indeed, in preferred embodiments of the present invention the expandedsplines 14 assume a non-spherical or substantially non-spherical shape,preferably asymmetric, especially but not limited to the spline portionsnear the distal tip 16 and/or the spline portions near the proximalanchor 18. Such overall shapes are non-limiting, and other overallbasket shapes, including substantially spherical shapes, asymmetricspherical shapes, non-spherical shapes, non-spherical asymmetric shapesand the like may suitably be used.

As depicted in FIG. 6, the splines 14 of the spline basket 12 may be ina compressed state within the lumen 48 of the guide catheter 46 and/orof the lumen of the hemostat penetrator tube 22. The splines 14 aredepicted in FIG. 6 as being in a compressed approximate or substantialelongate cylindrical shape. In such a compressed state the effectivelength of the splines 14 between the distal tip 16 and the proximalanchor 18 are substantially the same. Effective spline lengths betweenthe distal tip 16 and the proximal anchor 18 in the expanded basketshape of, for example, FIG. 5 are not so limited and, if desired, mayvary as described in further detail below.

FIG. 7 is an expanded side view of a portion of the basket 12 of thesystem 8 of FIG. 1 showing M-shaped, symmetric distal splines, accordingto the present invention. The distal basket portion 70 has distal splineportions 66 secured to one and the other by the distal tip 16. Theproximal basket portion 68 contains proximal spline portions 62. Theproximal spline ends 60 are secured by the proximal anchor 18 (notshown). Medial basket portions 72 and medial spline portions 64 aredisposed between the respective ends.

As depicted in FIG. 7, the splines 14, including medial portions 64 ofthe splines 14, expand or bow outwardly to assume an expanded,non-cylindrical shape, with the basket 12 having a proximal basketportion 68, a distal basket portion 70 and a medial basket portion 72there between. While the expanded splines are depicted in a spherical orsomewhat spherical orientation, the present invention is not so limited.Indeed, in preferred embodiments of the present invention the expandedsplines 14 assume a non-spherical or substantially non-spherical shape,preferably asymmetric.

FIG. 8 is a perspective view of the basket 12 of FIG. 7. Although eightsplines 14 are depicted, the basket 12 of the present invention may haveany useful number of splines. FIG. 9 is a right side view of theM-shaped basket embodiment of FIG. 7 depicting symmetric spline angles.As depicted in FIG. 9, the angles, θ1 through θ8, are all approximatelyequal at 45°. Such a relationship is a predetermined angularrelationship to offer a symmetric or substantially symmetric basket 12as viewed from a cross-sectional plane of the basket 12.

The present invention, however, is not so limited. For example, asdepicted in FIGS. 10 and 11, a predetermined angular relationship wherethe angles, θ1 through θ8, may vary may suitably be used. As depicted inFIG. 11, the angles θ1 and θ5 are approximately 90°, and the angles θ2through θ4 and θ6 through θ8 are approximately 30°. These angles arenon-limiting and any suitable arrangement of angles may be used. Such anon-symmetric angular relationship as depicted in FIGS. 10 and 11 may beuseful, if desired, to concentrate a greater number of splines 14 at aparticular location within the body, for example the right atrium of theheart.

FIG. 12 a side elevational view of one of the splines 14 of FIG. 7showing the M-shaped distal curve 74 of basket 12 at the distal splineportion 66. The spline 14 also contains a proximal recurve 76 at theproximal spline portion 62. Further the spline 14 is also depicted asbeing symmetric in its expanded state about a longitudinal axis L, whichis determined by the line segment axis from the proximal anchor 18 tothe distal tip 16. FIG. 13 is a perspective view of the spline 14 ofFIG. 12, further depicting the spline curvatures at the proximal splineportion 62 and the distal spline portion 66.

FIG. 14 is an exploded view of the distal M-shaped spline curve 74. TheM-shaped spline curve 74 contains distal incurvate inward bends 78 andexcurvate outward bends 80. Bend 78 is described as incurvate and/orinward because an apex 79 is directed towards the interior of the basket12. Bend 80 is described as excurvate and/or outward because apex 81 isdirected away from the interior of the basket 12. Bends 78 are useful incontrolling angles from which splines 14 exit from or emerge into thedistal tip 16, i.e., directed toward the exterior of basket 12. Thebends 80 turn the splines 14 back in a proximal direction towards theproximal anchor 18.

FIG. 15 is an exploded view of the proximal spline portion 62 of thespline 14 of FIG. 12. The proximal spline portions 62 contain proximalrecurves 76. The proximal recurves 76 include proximal incurvate bends82 having apices 83 and proximal excurvate bends 84 having apices 85.The proximal recurves 76 impart several important features to the basket12 of the present invention. The proximal recurves 76 allow for thegeometry and flexibility of individual splines 14 to vary at theproximal end 62 which allows the basket 12 to become asymmetric and tobetter conform to the contours of the right atrium, as described inconjunction with FIG. 42A below. Further, the proximal recurves 76 allowfor better placement of electrodes (not shown) at the proximal atrialtissue. Baskets common in the prior art do not often have good contactwith proximal atrial tissue, thereby adversely effecting electricalactivity detection thereat. Furthermore, the flexibility and geometry ofthe recurves 76 also permit enhanced electrode-tissue contact for theelectrodes placed not only on the proximal spline portions 62, but alsoon the medial spline portions 64 and distal spline portions 66.

FIG. 16 is an exploded view of the distal spline portion 66. The splines14 may contain portions of reduced spline widths 88 as compared tonormal or non-reduced spline widths 86. Here the reduced spline widths88 are depicted as being near the distal spline portion 66. Such reducedwidths 88 may increase spline flexibility, as these spline portions areproximal to the distal tip 16 (not shown). The distal spline portion 66may also include an alignment member 89 which, as described furtherbelow, is useful for aligning and/or securing the splines 14 within thedistal tip 16 (not shown). The reduced width portions 88 at the splinedistal portions also allows for less force to compress the basket 12, asdepicted in FIG. 6, during removal of the basket 12 from the patient.Further, the reduced spline widths 88 aid in the basket 12 in achievingthe substantially cylindrical shape, as depicted in FIG. 6. In otherwords, as compression of the basket 12 within a lumen 22, 48 goes fromthe medial basket portions 72 towards the distal basket portions 70, thereduced spline widths 88 allows the distal incurvate bends 78 to flexoutward or away from the compression force so that the distal splineportions 66 do not retain the inward bends 78, or simply stated thebends 78 pop outward during radial compression of the basket 12. Anotheradvantage of the distal M-Shaped spline curve 74 is that the distal tip16 is directed towards the interior of the basket 12 when the basket 12is deployed or is in its radially expanded state. This feature, ifdesired, keep the distal tip 16 away from distal heart tissue as thedistal spline portions 66 may extend beyond the distal tip 16 in thelongitudinal direction of the basket 14.

FIG. 17 is another embodiment of the spline 14 of FIG. 12. The spline 14of FIG. 17 contains proximal tangential curves 90. While the tangentialcurve 90 may not offer the same degree of spline flexibility and basketstability as offered by the proximal spline recurve 76, such a proximaltangential curve 90 may be preferred by some practitioners in certainatrial procedures.

FIG. 18 is a side elevational view of another spline 14 useful with thepresent invention. The spline 14 in FIG. 18 has a similar proximalspline recurve 76 as the spline 14 of FIG. 12. However, the spline 14 ofFIG. 18 has a D-shaped 92 distal end portion 66. Such a D-shaped distalend 92 is useful with certain embodiments of distal tips 16 that aredescribed below. FIG. 19 is a perspective view of the spline of FIG. 18showing spline curvatures in further detail. FIG. 20 is an exploded viewof the D-shaped spline portion 92 of FIG. 18. The distal spline portion66 has substantially flat portions 94 followed by the curved portions96. The curved portions 96 merge into the normal curvature of theoverall basket shape. The substantially straight portion 94 are usefulwith certain distal tip 14 designs and where spline emergence orentrance angles at the distal tip 14 are desired to be about 90°.

FIG. 21 depicts yet another spline 14 embodiment. The spline 14 of FIG.21 contains D-shaped distal portions 94, 96 at the distal spline portion66 and proximal tangential curves 90 at the proximal spline portion 62.Thus, the assembly 10 of the present invention may use any combinationof the above-described spline geometries.

Splines 14 may be flattened splines through the body of the spline 14having a substantial rectangular shape with rounded sides (see, e.g.,FIG. 34C). Throughout at least a major portion of the splines 14, thesplines 14 may be about 0.013 to about 0.035 inches wide (W1) and about0.002 to about 0.012 inches thick (T1), as depicted in FIGS. 22A through22D. A preferred width (W1) is about 0.022 inches. Spline thickness (T1)may depend on the overall size of the basket 12 with small sizedbaskets, for example less than 60 mm in nominal diameter, the thicknessmay range from about 0.002 inches to about 0.010 inches, with 0.004inches being preferred. For larger size baskets, for example greaterthan 60 mm in nominal diameter, the thickness may range from about 0.002inches to about 0.012 inches, with 0.006 inches being preferred. Thesedimensions are not limiting and represent normal or typical spline widthportions 86 and spline thickness portions 98.

Some portions of the splines 14 may have reduced with portions 88 and/orreduced thickness portions 100. Typically, these portions 88, 100 aredisposed at distal spline portions 66 near or at the distal tip 16.However, the present invention is not so limited at these reducedportions 88, 100 may be present in proximal spline portions 62 andmedial spline portions 64. The thinned spline portions 88, 100 may havea reduction in width and or thickness of several thousands of an inch.For example, the thickness (T2) of certain spline portions 100 may bethinned down to several thousands of an inch or to a thickness of about0.003 inches to 0.004 inches, or less. Such thinning of the distalspline segments 66 near the membrane tip 14 reduces stresses duringcapture of the splines 14 within the guide catheter 34. Low stress is anadvantageous feature during collapse for introduction, repositioning andwithdrawal of the spline basket. The width (W2) of the narrowed splinesegments 88 may be narrowed from about 0.013 to 0.035 inches to about0.008 to 0.014 inches. Such thinning aids the splines 14, when they foldup or collapse into the guide catheter 34, to overcome their tendency topush themselves apart and avoid them occupying more space in thecatheter 34. Thus, a low profile catheter system 10 may be providedaccording to the present invention.

FIGS. 23A and 23B depict a spline portion, such as spline portion 86,having a buckle point 102. The buckle point 102 may be ground into thespline 14 or formed by any other suitable technique. The buckle point102 is depicted as an inwardly curved notch, but other designs maysuitably be used. As depicted in FIGS. 23A and 23B, the buckle points102 provide the splines 14 with curvature inflection points, whichprovide the basket 12 with improved matching of the contours of theinterior of the heart. The buckle points 102 may be disposed at anylocation along the proximal spline portions 62, the medial splineportions 64 and/or the distal spline portions 66 shown in FIG. 21.Further, the number or frequency of buckle points 102 may also vary.

As depicted in FIGS. 24 and 25, the splines 14 may emerge from thedistal tip 16 at any useful emergence angle, a, with respect to thelongitudinal axis L, which is defined by a line segment from theproximal anchor 18 to the distal tip 16. For example, as depicted inFIG. 24, the emergence angle α may be about 45° or less than about 45°.As depicted in FIG. 25, the emergence angle α may be about 90°. Thesplines 14 may include a bend 78 which is useful for, among things,controlling the shape of the expanded splines 14 or basket 12. Thedistal tip 16 shown in FIGS. 24 and 25 is merely a schematic depictionof a general tip. Any of the below-described distal tips of the presentinvention may be used with any of the emergence angles described inconjunction with FIGS. 24 to 25. The angles are non-limiting, and anysuitable emergence angle or combination of emergence angles may be used.

FIGS. 26A through 26F depict a two-part welded distal tip 16, accordingto the present invention. FIG. 26A is a front perspective of distal tip16; FIG. 26B is a back or rear perspective of distal tip 16; FIG. 26C isperspective view of a top part of the distal tip 16; FIG. 26D is abottom view of the top part of the distal tip 16; FIG. 26E is a topperspective view of the bottom part of distal tip 16; and FIG. 26Fdepicts an alternate embodiment of the distal tip 16.

As depicted in FIGS. 26A through 26E, distal tip 16 may include a toppart 104 and a bottom part 108. The distal portions 66 of the splines 14are securably disposed within the distal tip 16. The top surface 106 ofthe top part 104 may have any suitable shape, such as a substantiallyflat surface 106 with rounded edges so that the distal tip 16 is anatraumatic tip, i.e., a tip that will not cause damage to atrial tissue.The bottom part 108 likewise should be free of any sharp edges orprojections to avoid atrial tissue damage. The top part 104 and thebottom part 108 are secured to one and the other by any suitable means.One non-limiting means and useful means is welding the two partstogether to provide a unitary distal tip 16. Such securement istypically performed after proper placement of the distal spline portions66 within the distal tip 16.

As depicted in FIGS. 26C through 26D, the top part 104 of the distal tip16 may include spline alignment posts 110. The spline alignment posts110 are spaced apart so that the splines 14 may fit between the splinealignment channels 112. The spline alignment posts 110 do not extendcompletely into the center of the distal tip 16, but terminate toprovide a center spline alignment portion 114 of the top part 104 of thedistal tip 16. The center spline alignment portion 114 is useful forreceiving the spline alignment members 89 of the distal portions 66 ofthe splines 14 into that region 114 of the distal tip 16. Thecombination of the center spline alignment portion 114 and the splinealignment channels 112 provide for, among other things, securablyholding the splines 14 in any desired predetermined angularrelationship. The number of spline alignment posts 110 may vary as thenumber of splines 14 may vary within the distal tip 16. The bottom part108 of the distal tip 16 may contain flat top and inner surface 116. Thesurface 116 may generally correspond to the bottom surfaces of thespline alignment posts 110. The bottom part 108 may also include araised central; portion 118. Desirably this raised central portion 118is substantially flat. The raised portion 118 is sized so that it can bedisposed within the center spline alignment portion 114 of the top part104 of the distal spline 16.

While the splines are securably held within the distal tip 16, thespline alignment channels 112 allow some movement of the spline 14. Forexample, spline portions may move upward and or downward with the splinealignment channel 112 to provide flexibility of the splines 14 at thedistal tip 16. If desired, an elastomeric material may also be placedwithin the two-part distal tip 16 to minimize tip voids and open spaces.

As depicted in FIG. 26F, the two-part distal tip 16 may include arounded or domed upper 106′ of the top part 104′. Such a rounded ordomed design may be useful in providing more rounded surfaces for theatraumatic distal tip 16.

The distal tip 16 of FIGS. 26A through 26F may be made of any suitablebiocompatible material. Although metal materials are preferred, plasticmaterials may be used.

FIGS. 27A through 27C depict an alternate embodiment of the distal tip16 of the present invention, i.e., a filament wound and encapsulateddistal tip 120, in which FIG. 27A is a front perspective view of thefilament wound and encapsulated distal tip 120; FIG. 27B is a side viewof the filament wound and encapsulated distal tip 120; and FIG. 27C is aback or rear perspective view of the filament wound and encapsulateddistal tip 120. FIGS. 27D and 27E are exploded views of the filamentwrapping for the filament wound and encapsulated distal tip 120, inwhich FIG. 27D is a top perspective view thereof and FIG. 27E is a backor rear perspective view thereof. The filament 124 is wrapped over,under and between the splines 14 and over and under the spline alignmentmembers 89 to secure the splines 14 in any desired predetermined angularrelationship.

The splines 14 are secured to each other at the filament wound andencapsulated distal tip 120. Tip 120 may be described as being a“filament wrapped and encapsulated” or a “suture wrapped andencapsulated” tip 16. Tip 120 is not limited to the use of suturematerials and any suitable filaments, threads, wires and the like may besuitably used. Advantageously, the filament wound and encapsulateddistal tip 120 is a low profile tip. Further, filament wound andencapsulated distal tip 120 has no open spaces, such as slots or holes,common with some basket catheters of the prior art. Such open spaces orholes present in tips of the prior art allow for entry of blood cells,thereby causing or having the potential to cause blood clot formation orthrombogenesis. As described below, the splines 14 are secured to eachother at their circular alignment members 89 by the use of a suture(s)124, filament(s) 124, wire(s) 124 or thread(s) 124. Multiple sutures124, filaments 124, wires 124 or threads 124 may be used. After thesplines 14 are so secured, the circular alignment members 89 of thesplines 14, including the securing suture(s) 124, filament(s) 124,wire(s) 124 or thread(s) 124 are fully or substantially or partiallyencapsulated with an encapsulant 122 to provide the filament wound andencapsulated distal tip 120.

As depicted in FIGS. 27D and 27E, the circular tip spline alignmentportions 89 of the splines 14 are aligned or substantially aligned witheach other. Filaments(s) 124 are laced, looped or wound between, overand under the splines 14 at the circular tip spline alignment portions89. A single filament or multiple filaments 124 may be used.Advantageously, the filament(s) 124 is laced, looped or wound betweenevery adjacent spline portion. As depicted in FIGS. 27D and 27E, thefilament(s) 124 is laced, looped or wound about opposite splineintersections or alternating spline intersections and then iscrisscrossed in a similar fashion until all or substantially all of thespline intersection locations are secured.

The filament 124 may include any suitable material. The use of hightensile strength fibers, such as electrospun, braided or monofilamentmay be used. Some non-limiting examples include, but are not limited to,for example: Dyneema Purity® (Ultra High Molecular Weight Polyethyleneor UHMWPE), Spectra® fiber (UHMWPE), Polyethyleneterephthalate or PET,polypropylene, etc. Metallic wires, such as stainless steel or nitinol,may also be used, but non-metallic fibers are preferred for theirgreater flexibility. The filament(s) 124 may be tied or twisted togetherto secure the circular tip or alignment portions 89 of the splines 14.The filament(s) 124 may be twisted or tied together at locationsinterior to the spline basket 12. The tied together circular tip oralignment portions 89 and the filament(s) 124 are then encapsulated withan encapsulant 122. One useful encapsulant 122 is polyurethane, butother biocompatible encapsulants may suitably be used. The encapsulant122 is also disposed between the spline intersection points to providethe tip 120 of the present invention.

Some advantages of the filament wound and encapsulated distal tip 120 ofthe present invention include, but are not limited to improvedflexibility over tips of the prior art; reduced thrombogenicity;significantly smaller overall tip size; transparency under fluoroscopy;no MR artifacts; superior strength, i.e., equal to or greater than 15times the strength of steel of the same diameter; superior adhesive bondstrength; resistance to cutting (scissor action); and very smalldiameters, as low as 25 decitex (dtex).

As depicted in FIGS. 27A through 27C, the filament wound andencapsulated distal tip 120 has an atraumatic profile with a smooth,somewhat rounded upper surface, an inwardly contoured bottom surface andsmooth side surfaces. The amount of encapsulant 122 may be minimized toprovide maximum spline flexibility.

FIG. 28A depicts another embodiment of the distal tip 16 in whichtwo-part welded distal tip 126 with half splines is provided. Asdepicted in FIG. 28A, two-part tip 126 includes a top portion 128insertable through a bottom portion 130. A space or detent is providedin either or both portions 128, 130 so that distal ends 67 of thesplines 14 may be securably inserted therein. The portions 128, 130 ofthe two-part tip 126 are securably joined together to securably affixthe distal spline ends 67 therein. The portions 128, 130 of the two-parttip 126 may be secured to each other by spot welds 132, but othersecuring techniques may suitably be used. Although the splines 14 aredepicted as emerging from the sidewall of the two-part tip 126, thepresent invention is not so limited. If desired, the splines 14 mayemerge from the top portion 128 (not shown) and/or the bottom portion130 (not shown). The emergence angle of the splines 14 from the two-parttip 126 may include any of the above-described emergence angles. Thesplines 14 depicted in FIG. 28A may be referred to as half-splinesbecause these splines have both distal spline ends 67 and proximalspline ends 60.

FIG. 28B depicts another embodiment of the distal tip 16, in which anitinol shrink ring tip 134 according to another aspect of the presentinvention. Spline ends 67 may be disposed within the tip 134. The tip134 has a compression ring 138 and a core post 136. The spline ends 67are disposed within and secured by the tip 134. The ring 138 may be madefrom metallic, nitinol shape memory metal, shrink tubes. It may bemachined at room temperature to design specifications, and then chilledso it can be expanded and stored. One may slip the ring 138 over themated spline ends 67 and post 136 and assemble quickly. As the ring 138comes up to room temperature it shrinks and provides a very strongcompression fitting to secure the spline 14 within the tip 134.

FIG. 28C depicts a tip 140 which may also be used with the presentinvention. A cap 144 and a base 146 may be secured to each other, by forexample spot welding, via a square rivet 142. The square rivet 142 ispassed through alignment square holes 148 punched in splines 14, asdepicted in FIG. 28D. The splines 14 do not directly pass through thedistal tip members 144, 146. In other words, the splines 14 do not passthrough a sidewall of tip 140, as no sidewall is present between thedistal tip members 144, 146.

In another embodiment of the present invention, the tips of the presentinvention may include a magnetic tip (not shown). With previouslydescribed constraining tips spline lengths should be about identical inorder for the basket to collapse evenly into guide catheter. If atriumoutline shape deviates from approximately cylindrical or oval, thenequal length splines may not contact all endocardial surfaces. A way tocircumvent this problem is to allow the splines to be of differentlengths (to match the atria), and allow the tip to “assemble” itself insitu when deploying. The tip may also “disassemble” itself when beingcaptured into the guide catheter. This design may be achieved by using asmall magnetic portion on each spline that “self assemble” themselvesinto a tip when deployed from the guide catheter, and disassemblethemselves (i.e., magnets pull apart) when the basket is collapsed intothe guide catheter. It may be necessary to place an elastic threadbetween each magnet, pulling them close enough for magnetic force topull into assembly. If the splines follow the inside wall of the heartduring diastole, then the splines need to buckle or deform duringsystole. The buckling will bring parts of the spline out of contact withthe endocardium. Deformation will move the electrodes to differentlocations on the endocardium, confusing the mapping software. Note that,during atrial fibrillation, the heart remains close to its diastolicdimensions during its entire contraction cycle. This reduces thesignificance of this effect, making the basket design easier. In orderfor the basket to collapse into the guide catheter the splines need tobe the same length but would need to be different lengths in order tofollow locally distended parts of the atrium. A magnetic tip woulddisassemble as the catheter goes into the guide catheter. An elasticthread could be used between them so that the magnetic field then grabsthem the rest of the way.

FIG. 29 depicts another embodiment of a distal tip 16, in which anencapsulated tip 150 is provided. The encapsulated tip may include anysuitable flexible and/or elastomeric material. The overall profile ofthe tip 150 may be larger than for the filament and encapsulated tip 120as tip 150 may not contain any filament wrapping or securement means.The encapsulated or molded tip 150 may be made from any suitablematerial. In one embodiment of the present invention, the encapsulatedor molded tip 150 may be made from polyurethane, polyester block amideor silicone.

FIGS. 30A and 30B depict another embodiment of the distal tip 16, inwhich a membrane distal tip 152 is provided. The membrane tip 152 mayinclude an inner membrane or film 156 and an outer membrane or film 154for securing the distal portions 66 of the splines 14. The distalportions 66 of the splines 14 may simply cross each other between thetwo membranes 154, 156. The membranes 154, 156 may be bonded, forexample adhesive bonding, thermal bonding, and the like, together toprovide the membrane tip 152.

The splines 14 may simply cross within the membrane tip 152. No separateconnection between the splines 14 within the membrane 152 is needed. Ifdesired, a connection (not shown) between the splines 14 may beprovided. The inner membrane 156 and the outer membrane 154 may beadhesively bonded to all splines 14 within the membrane tip 152.Further, the inner membrane 156 and outer membrane 154 may be adhesivelybonded to each other at locations between the splines 14. All elementsmay then be placed into fixture (not shown) so as to ensure the properlinear and angular orientation of the elements and then heat bondedtogether.

The present invention is not limited to the use of the inner membrane156 and outer membrane 154 to form the membrane tip 152. Additionalmembrane layers or films may be used. The membrane tip 152 may have anysuitable shape, for example a circular shape, an octagonal shape, andthe like. Further, matched diameter adhesive pads (not shown) may beplaced between splines 14 to add additional support beyond justmembranes 154, 156. The adhesive pads between the splines 14 at themembrane tip 152 may fill in gaps between splines 14, thereby providinga slightly larger area for adhesive bonding, if desired. Thus, in eitherembodiment the width and/or thickness of the tip membrane 152 isminimal, i.e., less than the thickness of the splines 14, or about thesame thickness of the splines 14 or even just slightly larger than thethickness of the splines 14. In any case, the tip membrane 152 does nothave an appreciable sidewall as compared to the tips of the prior art.

Further, the tip membrane 152, including the inner membrane 156 andouter membrane 154, may be made from any suitable polymeric material,preferably non-elastic polymeric material, including flexiblenon-elastic polymeric material. In one embodiment the membranes 154, 156may be made from a polyimide material. Desirably, the membranes 154, 156are not made from polytetrafluoroethylene, i.e., PTFE, includingexpanded polytetrafluoroethylene, i.e., ePTFE.

FIGS. 31A through 31D depict an embodiment of the proximal anchor 18 ofthe present invention, in which a slotted proximal anchor is provided.FIG. 31A is a perspective view of the proximal end 160 of the slottedanchor 158. FIG. 31B is a cross-section view of the distal end 162 ofthe slotted anchor 158 taken along the 31B-31B axis. Slotted anchor 158has an open diameter or open lumen 164. The open diameter or lumen 164allows wires, flex circuits, etc. from the spline basket 12 to passthrough the anchor 158. The proximal end 160 of the slotted anchor 158presses into an inner diameter or lumen of a catheter shaft 20C or isotherwise connected to the catheter shaft 20. Anchor 158 also includesspline-receiving slots 168. The number of spline-receiving slots 168typically is equal to the number of proximal spline end portions 60, andis shown in these drawings as a quantity of eight. As depicted in FIGS.31A and 31B, the spline-receiving slots 168 may be evenly spaced toallow for the basket splines 14 to be equally spaced in the desiredangular position. The present invention, however, is not so limited, andany number of proximal spline end portions 60 and spline-receiving slots168, oriented at any desired relative angles may suitably be used.

One function of the anchor 158 is to attach the basket splines 14 to thecatheter 20 and orient the splines 14 to give the basket 12 the propershape and ensure it remains straight (not bent) upon collapse into theguide catheter 46. The anchor device 158 is a means by which to orientthe basket splines 14 on the proximal end 68 of the spline basket 12 andto fasten them together. Additionally, the anchor 158 affixes the basketsplines 14 to the catheter shaft 20. The anchor 158 may be fabricatedfrom a single piece of material, e.g., a hypotube, or multiple sectionsthat are attached (i.e. welded, glued, etc.) together. The slots 168 aresized to fit the basket splines 14 and the slot length ensures splines14 are positioned accurately, which aids in even collapsing of thebasket 12. The slots 168 have adequate length to allow for the variablepositioning of the basket splines 14. The basket splines 14 may beattached to the anchor 158 by adhering with glue, welding, crimping orthe like. Additionally, a ring (not shown) may be slid over the anchor158 to hold the basket splines 14 in place. The outer ring (not shown)may be crimped, swaged, welded, glued, etc. to the outside 166 of theanchor 158 or the outside of the catheter shaft 20. The angular spacingof the slots 168 may be varied to accommodate the amount or number ofbasket splines 14 to be attached as well as to get the desired spacingof basket splines 14. As depicted in FIG. 31B, one typical angularspacing is 45° degrees. The proximal end 160 of the anchor 158 is sizedto press fit into a catheter shaft. It can be changed to accommodate anydesired catheter dimensions. Additionally, the proximal end 160 can havegeometry to mechanically lock the anchor into the catheter shaft (i.e.,barb(s), serrated edges, ribs, etc.). The inner diameter or lumen 164 ofthe anchor 158 is open to allow for catheter wiring, flex circuits, etc.to pass through the catheter shaft. Additionally, the wiring, flexcircuits, etc. could be, if desired, run on the outer diameter of theanchor device 158. Additionally, when the splines 14 are inserted intothe anchor 158 and it is press fitted into the catheter shaft 20C, theanchor 158 locks into the catheter shaft 20C to enable the shaft 20 tobe rotated without the basket 12 slipping inside the catheter shaft 20C.Some non-limiting advantages of the anchor 158 of the present inventioninclude, but are not limited to, ease of allowing fastening or gatheringof basket splines 14 made of any material; may be fabricated from anysuitable material or multiple materials; allows for variable positioning(length and angular) of the basket splines 14 to ensure even collapsinginto the recovery sheath device; and provides sufficient clearance fordevice wiring. Further, as depicted in FIG. 31D, the anchor 158 mayinclude a hemostat plug 170 into which a spline tube 172, which maycontain a spline 14, passes to provide a sealed proximal spline tubelumen. The hemostat plug 170 may also be useful in securing the slottedanchor 158 to the catheter shaft 20.

FIGS. 32A through 32C depict another embodiment of a proximal anchor 18of the present invention, in which an anchor 176 is provided. The spline14 may contain a notch 174 at the spline proximal end 60. The anchor 176includes an inner ring 181 having spline alignment slots 180 throughwhich the spline ends 60 may pass. The spline ends 60 are interlockedwith the anchor 176 via the spline notch 174 and alignment detent 184.This interlock provides both excellent pull out retention and automatic,accurate alignment of all splines 14 with respect to each other so thatthey collapse neatly and reliably into the guide catheter 46 duringintroduction and removal of the catheter 20. Once the splines 14interlock with the anchor 176, a second thin-walled tubing 178 isinserted over the anchor 176. This tube 178 prevents the splines 14 fromdisengaging their interlocks in the anchor 181. A complete lack ofapplicable forces on the internal anchor ring, adhesive and a slightinterference fit between the external anchor and internal anchor ringsprevents pull out of the inner anchor during use.

FIG. 33A is a perspective view of the basket 12 showing spline tubes 172having spline tube assemblies 185 and exposed electrodes 186. FIG. 33Bis a side elevational view of the basket 12 of FIG. 33A. The splinetubes 172 are disposed over the splines 14 except at distal basketportion 70 where the splines 14 emerge from the distal tip 16. Theexposed electrodes 186 are spaced along spline distal portions 66,spline medial portions 64 and spline proximal portions 62. The number ofexposed electrodes 186 may vary. The electrodes 186 are part of a flexelectrode circuit 188, which will be described in further detail below.

FIGS. 34A and 34B are exploded partial cross-sectional views of thespline tubes 172 and spline tube assemblies 185. The splines aredisposed within a lumen 208 of the spline tubes 172. As depicted inFIGS. 34A and 34B the splines 14 are not fixed to lumen 208 of thespline tube 172. The spline tube 172 may be slidingly assembled over thespline 14 to provide some interference there between. The spline tube172 may desirably include a flexible material so that the lumen 208 ofthe spline tube 172 takes an elliptical shape substantially matching thecross-sectional extents of the spline 14.

FIG. 34C depicts a cross-section of the spline 14 of the presentinvention. As depicted in FIG. 10, spline 14 may have a flat orsubstantially flat upper surface 190, a flat or substantially flat lowersurface 192, and rounded sidewalls 194, 196. The present invention,however is not so limited, and the upper surface 190 and/or the lowersurface 192 may be rounded or otherwise have curvature, includingconcave and/or convex curvatures. The splines 14 desirably includeand/or are made of a super-elastic material so that the splines bowoutwardly into the basket shape 12, including asymmetric basket shapes.Any suitably super-elastic material may be used. Preferably, the splinesinclude or are made of nitinol. If desired, the spline material may alsobe a shape memory material, such as but not limited to shape memorynitinol. Further, the splines 14 may be about 0.013 to about 0.025inches wide and about 0.002 to about 0.010 inches thick. Thesedimensions are non-limiting and other dimensions may suitably be used.

FIGS. 34D through 34F depict radiopaque markers 198 useful with thespline tubes 172 and spline tube assemblies 185 of the presentinvention. As depicted in these figures, the radiopaque marker 198 maybe disposed over a portion of the spline 14 that is near an electrode186. Desirably, the radiopaque marker 198 is securably fixed to thespline 14. A significant useful feature of the current design over priorart is the radiotransparency of the flex circuit electrodes 186(described below). This feature allows the separation of thefluoroscopic images of the splines and electrodes provided by theradiopaque markers 198 from the signal gathering function of theelectrodes. This feature allows distinguishable patterns of electrodemarkings to be produced under fluoroscopy without modifying orcompromising the electrogram gathering performance of the electrodes186.

FIGS. 34G through 34H depict a non-limiting arrangement of radiopaquemarkers 198 with the spline basket 12 of the present invention. Thenumber of radiopaque markers 198 may vary along each spline 14 and mayvary from spline to spline. These figures represent the two-dimensionalshadowgraphs produced by fluoroscopy. FIG. 34G is a side perspectiveview of the basket 12 under fluoroscopy. Each spline 14 has fourradiopaque markers 198 identifying a particular electrode on aparticular spline 14. For example, the four radiopaque markers 198 atS1E8 refers to the unique combination set of {spline 1, electrode 8}; atS2E7 refers to {spline 2, electrode 7}; at S3E6 refers to {spline 3,electrode 6}; at S4E5 refers to {spline 4, electrode 5}; at S5E4 refersto {spline 5, electrode 4}; at S6E3 refers to {spline 6, electrode 3};at S7E2 refers to {spline 7, electrode 2}; and at S8E1 refers to {spline8, electrode 1}. In addition other electrodes 186 are marked with onemarker 198 or two markers 198. Generally, even numbered splines have twomarkers 198 at each electrode position, and the odd numbered splineshave one marker 198 at each electrode position not marked with the fourmarkers. Such an arrangement, as depicted in FIG. 34H allows apractitioner to easily note the orientation of the basket 12 underfluoroscopy, including the location of the distal tip 16 and all of theelectrodes 198. FIG. 34I depicts that when the basket 12 of FIG. 34 G isrotated, individual splines 14 and electrodes 186 become apparent withthe placement of the radiopaque markers 198. For example, in FIG. 34I,the identity of each pair of crossed splines (S7 & S8, S1 & S6, S2 & S5,S3 & S4) would be ambiguous on one side of the crossing if eachelectrode were marked with a single RO marker. Further, a portion of thecatheter body 20 (not shown) may also include radiopaque markers (notshown) to further aid the practitioner under fluoroscopy.

FIGS. 35A through 35H depict the spline tubes 172 with the spline tubeassemblies 185 of the present invention. As depicted in FIG. 35A, thespline tube 172 is an elongate tubular member. The spline tube 172 orspline tube assembly 185 includes a proximal end 200 and a distal end202. As depicted in FIG. 35A, a portion of the spline 14 may emerge fromthe tube distal end 202, where it may engage the distal tip 16. Thepresent invention, however, is not limited to flexible tube assemblies185 only with the use of the basket 12. The flexible spline tubeassemblies 185 may be used by them themselves or with any other devicewhere electrical activity within a body is to be monitored. In somecases spline tube assembly 185 a may not need to have a spline portion14 or similar component exiting from the distal end 202. The spline tubeassembly 185 of FIG. 35A has two flex circuits 188, each with fourelectrodes 186, mounted sequentially on the spline tube 172, while thespline tube assembly of FIG. 35B has one flex circuit 188 with eightelectrodes 186. These numbers of flex circuits and electrodes arenon-limiting.

FIG. 35C is a partial exploded view of the spline tube assemblies 185,185 a of FIGS. 35A and 35B. As depicted in FIG. 35C, the spline tubeassemblies 185, 185 a may include a first flex circuit 188 a havingelectrodes 186 and a second flex circuit 188 c also having electrodes186. The first flex circuit 188 a may have a transition portion 188 bwhere the first flex circuit 188 a transitions to a position on the tube173 below that of the second flex circuit 188 c. In such a manner,multiple flex circuits may be places on the tubes 172, while stillorienting the electrodes 186 in substantially one direction, typicallyin an outward direction from the spline basket 12.

As depicted in FIGS. 35D and 35E, the proximal end 200 of the splinetube 172 may be sealed with a plug 204 of material. The material may bean adhesive, polymer or any other useful material having sealingcharacteristics. The distal end 202 of the tube 172 may also be sealedwith a plug 206 of material. Such sealing closes the internal lumen 208of the spline tube 172 against the flow of fluids, including bodyfluids, such as blood. Such sealing also secures the spline tube 172 tothe spline 14. The present invention, however, is not limited to havingjust the proximal end and/or distal end so sealed or secured andintermediate portions may also be so sealed or secured.

As depicted in FIGS. 35F and 35G, the flex circuit portions 188 a, 188 band 188 exiting the spline tubes 172 may be embedded into the wall ofthe spline tube 172. The present invention is, however, not so limitedand as depicted in FIG. 35H, a portion of the flex circuit 188 maytransition from the outer surface 208A and past the inner surface 208Bso that it is disposed within the lumen 208 of the tube 172. The splinetube 172 and the spline tube assembly 185 may comprise a biocompatiblepolymer such as a polyether block amide material, such as Pebax®. Otherflexible biocompatible polymers, such as polyesters, silicones (e.g.Silastic®), silicone rubber, urethanes (e.g. Texin® and Pellethane®),and the like may suitably be used.

FIGS. 36A through 36E depict an embodiment of the flex circuit 188 as aflex circuit strip 212 of the present invention. The flex circuit 212includes a proximal end 214 and a distal end 216. Towards the distal end216 is an electrode-containing portion 218. The medial portion 220 maybe free of electrodes. The flex circuit strip 212 may contain wings 222.These wings are useful in securing the flex circuit 212 to tubularmembers, such as spline tubes 172, especially where it is desirable tokeep the electrodes 186 as substantially unidirectional flat electrodes.The flex circuit or electrode assembly strip 188 may have a thicknessfrom about 0.001 inches to about 0.010 inches, more desirably from about0.005 inches to about 0.008 inches.

FIG. 36A is a top view of the flex circuit strip 212 showing electrodes186 disposed on the upper surface 224 of the flex circuit substrate 236.The flex circuit substrate or polymeric substrate 236 may comprise apolyimide material, such as KAPTON polyimide available from DuPont,which is suitable for short term (single use medical device) or longterm (medical implant) contact with skin, tissue or blood, depending onthe intended application, but other suitable materials may be used, suchas the above-described materials for the spline tube 172 or the splinetube assembly 185. At the proximal end 214 electrical pads are disposedon the upper surface 224. FIG. 36B is a bottom view of the flex circuitstrip 212. Electrical traces 228 are disposed on the bottom surface 226of the substrate 236. The traces run from location underneath theelectrodes 186 to locations underneath the electrical pads 232. Asdepicted in FIGS. 36C through 36E, metal plated holes or vias 230electrically connect individual traces to individual electrodes 186. Ina similar fashion vias 234 connect individual electrical traces 228 toindividual electrical pads 232.

As depicted in FIG. 36F, the flex circuit 212 may contain upper surfacecoverlays 238 to cover those areas of the upper substrate surface 236Anot having electrodes 186 or connection pads 232. Likewise, if desired,bottom surface coverlays 240 may cover part or all of the electricaltraces 228. Upper coverlays 238 and lower coverlays 240 are bonded tothe substrate 236 with the use of suitable adhesive 239, usually acrylicadhesive. Desirably, the upper flex circuit axis S is substantiallysmooth, i.e., the coverlays 238 and the electrodes 186 beingsubstantially the same height. The present invention, however, is not solimited, and electrodes may be raised slightly above the substratesurface with the use, for example, of strips of material disposedbetween the substrate 236 and the electrodes 186. Alternatively, theelectrodes may be depressed slightly below the substrate surface, asshown in FIG. 36F. The coverlays 238, 240 may comprise a similarmaterial as the substrate 236, but different materials may suitably beused.

FIGS. 37A through 37C depict an alternate embodiment of the flex circuit188. As depicted, electrical traces may run on both sides of the flexcircuit substrate 236. For example, four electrodes, 186 a, 186 b, 186 cand 186 d are depictured in FIG. 37A. In the top view of FIGS. 37A and37B no electrical traces run on the upper surface 224 between theelectrodes 186. However, proximal to the electrodes, electrical traces228 for two electrodes 186 c, 186 d run on the upper surface 224, andthe electrical traces for the other electrodes 186 a, 186 b run on thebottom surface 226 of the flex circuit substrate. The electrical trace228 for electrode 186 c transitions from the bottom surface 226 to theupper surface 224 by means of a trace-to-trace via 244. Such asarrangement of electrical traces 228 as depicted in FIGS. 37A through37C may make for a more overall compact flex circuit.

FIGS. 38A and 38B depict a flexible electrode assembly strip 247. Theflexible electrode assembly strip includes a flex circuit or electrodeassembly strip 188, 236 pressed into the substrate 246 of a flexiblepolymeric material, such as any of the above-described materials for thespline tube 172 or the spline tube assembly 185. The flex circuit orelectrode assembly strip 188, 236 may also be thermally, compressivelyand/or adhesively bonded onto or into the substrate 246. While thesubstrate 246 is depicted as being a strip or being planar, the presentinvention is not so limited. The substrate could be tubular with orwithout an open lumen. As depicted in FIG. 38B the electrode assemblystrip 188, 236 is pressed into the substrate wall 246 b while leaving asubstantially smooth upper surface 246A and lower surface 246C. Ifdesired portions of the flex circuit 188, 236, for example thoseportions not containing electrodes, may be disposed between multiple twoor more substrates 246, either in planar or tubular form. When coveringthe electrodes with a cover or substrate of polymeric material, it isdesirable to remove cover or substrate material so that the electrodes186 remain exposed.

All components, i.e., splines, electrode flex circuits, electrodeelevation strips (used to raise the surface of the electrodes above thesubstrate, if desired; not shown), radiopaque marker strips aredesirably thin, flat, planar elements. In a simple design, theseelements may be stacked and adhesively bonded to each other.Alternately, a length of flexible tubing or membrane can be slid overthe bonded spline/radiopaque marker/flex circuit/electrode elevationstrip in order to contain all parts within a single body. This tube ormembrane can be shrunk in place for a tight, contained fit using eitherheat shrink tubing or tubing that is chemically expanded (e.g., byabsorption of alcohol or other chemical) for assembly, and thencontracts when the chemical evaporates.

FIG. 39 depicts yet another alternate embodiment of a flex circuit 188having laterally staggered electrodes 186.

FIGS. 40A and 40B depict the use of quad wires 248 which connectproximal end 214 of the flex circuit 188. Individual quad wires 248 areconnected to individual electrical pads 232 at the proximal ends 214 ofthe flex circuits. The quad wires 248 then are routed through thecatheter body 20 and handle 28 to the catheter connector located at theproximal end of the handle 28.

FIGS. 41A and 41B depict a portion of the catheter shaft 20 as having abraided shield 250 that minimizes possible electro-magnetic interferencefrom outside sources. The catheter 20 may also have anti-kink beadingsections 252 or 254, which provide greater support to prevent kinking ofthe catheter 20. Flexibility of the catheter body 20 may also becontrolled which advantageously aids in having the basket 12 moreclosely match the contours of the heart.

FIGS. 42A through 42C further depict asymmetric basket shapes for basket12. FIG. 42A is a side view of the asymmetric basket shape is depicted.The basket shape is asymmetric in this view in that, among other things,the basket shape is not spherical and/or the proximal spline portions 62may contain different degrees of curvature or bends 82, 84. These bends82, 84, also known as a dimple end and/or a puckered end, allows thebasket 12 to compress when the heart contracts. In other words, theproximal portion 68 of the basket 12 is designed with greaterflexibility to ensure, among other things, improved contact of thesplines 14 with interior surfaces of the heart wall.

While one overall basket shape is depicted in FIG. 42A, it may bedesirable to have different basket shapes, for example, a right atrialbasket shape and a left atrial basket shape. These different baskets mayhave different basket outline shapes and therefore different compliancesof the individual splines. These differences may allow each shape tooptimally conform to the differently shaped left atrium and rightatrium. In addition, each shape may come in several different overallsizes. Note that the specific shape shown in FIG. 42 is not intended torepresent an “atrial shaped basket”, but is instead an arbitrary shapethat illustrates the design features required to fabricate an asymmetricbasket that will successfully collapse within a guide catheter.

FIGS. 42B and 42C are an end views of the basket 12 of FIG. 42A. Asdepicted in FIG. 42B, all spline portions are substantially equidistantfrom the center longitudinal axis L and/or tip 16 or are substantiallyin the center of the overall basket outline C as depicted. As depictedin FIG. 42C, all spline portions are not substantially equidistant fromthe center longitudinal axis L and/or tip 16 or are not substantially inthe center of the overall basket outline C as depicted. Such asymmetryprovides for improved basket performance by more closely matching theshape of the atria of the heart. The splines 14 in FIG. 42A have anequal or substantially equal longitudinal length. The varying distancesof the medial portions 64 of the splines from the center longitudinalaxis L results from, in part, the flexibility of the splines 14 at theproximal spline portions 62 due to the inclusion of the bends 82, 84.While the longitudinal lengths of the splines 14 are equal orsubstantially equal in FIG. 42A if the basket 12 is in its compressedstate, the present invention is not so limited, and splines 14 ofvarying lengths may be suitably used. Such varying lengths may beachieved by imparting geometries to different bends 82, 84. For example,some bends may have greater inward longitudinal extents than other bendssuch that, when compressed with the guide catheter 46, all the splines14 of the basket 12 have an equal or substantially equal net linesegment between the anchor 18 and the tip 16. When the basket 12 isexpanded, the bends 82, 84 may “relax” and provide a basket assembly 12with splines 14 of net different lengths, for example spline 14 a havingan effective longer length than spline 14 b. Such asymmetry provided by,in part, splines 14 of varying lengths provide for a closer matching ofthe shape of the basket 12 with interior portions of the heart, i.e.,the atria, as the heart is beating.

In a similar fashion, the bends 78, 80 at the distal basket portion 70also provide for asymmetry, if desired. As depicted, both proximal anddistal spline portions 62, 66 may have different recurves or incurvatebends to more effectively match the shape of a typical atrium. Differentproximal recurves with different lengths and/or angles compensate fordifferent spline lengths so that the basket may be disposed within theguide catheter where the splines would have the same or about the sameeffective length when the basket is compressed, but will have differenteffective lengths when the basket is expanded.

The apparatus, system or devices of the present invention may includeelectrodes are configured as Monophasic Action Potential (MAP)electrodes, where a single electrode at each site is configured tointimately contact the tissue, and a second electrode at each site isconfigured to face away from the tissue, acting as an MAP “reference”electrode. An electronic Data Acquisition System may be configured torecord the electrograms produced by the catheter as MAP electrograms.The electronics Data Acquisition System may also be selected to recordthe electrograms produced by the catheter as either standard unipolarelectrograms, bipolar electrograms or as MAP electrograms. Further, theelectrodes may be configured as Modified Monophasic Action Potential(m-MAP) electrodes, where a single electrode at each site is configuredto intimately contact the tissue, and a second electrode placedintermediate between two or more sensing (i.e., tissue facing)electrodes, which is configured to face away from the tissue, acting asan MAP “reference” electrode for multiple sensing electrodes. Thecurvature of the splines is specifically chosen to match the curvatureof a “typical” atrium for the purpose of enhancing electrode to tissuecontact, producing the contact force required for quality MAP mapping.The splines may be curved at the proximal end with different lengthsegments in order to compensate for the different spline lengths thatresult from matching the splines to the shape of a typical atrium; whereequal spline total length (tissue contact segment plus recurve segment)is required to allow collapsibility for introduction and withdrawal ofthe catheter through the second elongate tube.

FIGS. 43A and 43B are bipolar electrograms 262, 264 obtained from animalstudies. In FIG. 43A the electrograms 262 were obtained from the use ofthe system 10 of the present invention. In FIG. 43A, the atrial signals258 are much larger than the ventricular signals 260 on electrodes A3,A5, A7, B7 and C3. Further in FIG. 43A, the atrial signals 258 areapproximately equal to the ventricular signals 260 on electrodes B5, C1and C5. Moreover, in FIG. 43A, the electrogram traces I, aVF and V1 arenot basket signals. In general the atrial signals 258 are much largerthan or equal to the ventricular signals 260. This allows a practitionerto more easily map the atrial signals within the heart to locate hearttissue causing heart fibrillations. The practitioner may suitably ablatesuch areas.

FIG. 43B depicts electrograms 264 obtained from animal studies using acommercially available prior art basket catheter. In FIG. 43B, atrialsignals 258 are absent on electrodes A1, A5 and A7. Also in FIG. 43B,the atrial signals 258 are smaller than the ventricular signals 260 onelectrodes A3, B5 and B7. Further in FIG. 43B, the atrial signals 258are approximately equal to the ventricular signals 260 on electrode B3.Still further in FIG. 43B, the atrial signal 258 are larger thanventricular signals 260 on electrodes B1, C1, C3 and C5. Moreover, inFIG. 43B, the electrogram traces I, aVF and V1 are not basket signals.In general, the atrial signals 258, when present, are much smaller thanventricular signals 260 on some electrodes, but may also be larger onother electrodes. The recorded signals of FIG. 43A represent asignificant improvement over the recorded signals of FIG. 34B. While notbeing bound by any theory, it is believed that the substantially flat,single sided flex electrodes 186 of the present invention with thedescribed flex circuits and spline tube assemblies, superior contact andcontact force generate higher atrial signals from the heart whilereducing the ventricular signals from the heart.

Further, the improved basket geometries of the present invention alsocontribute to improve mapping of the atrial signals as the baskets ofthe present invention are not only more stable within the atrium of thebeating heart, but also can flex and contour to the varying complexitiesof the beating heart.

The devices, systems and assemblies of the present invention are usefulin overcoming the problems or deficiencies associated with mapping ofthe right atria and the left Atria, especially when used in conjunctionwith atrial fibrillation ablation. Problems or deficiencies with typicalprior art or presently available commercial devices include (a)positional instability of basket during mapping and data analysis times,(b) positional instability of basket during ablation, (c) lack ofproximal basket electrodes, (d) poor electrode contact with atrialtissue typically yields poor signal (atrial) to noise (ventricular)ratios, (e) lack of electrode contact (no measurable atrial signals),(f) radiofrequency (RF) noise interfering with atrial signals recording,(g) spline lateral bunching, (h) electrode sliding (i.e., changingposition) during heart contraction, (i) poor spline/electrodeidentification under fluoroscopy, and/or (j) poor performance in leftatrial (LA) transeptal procedures.

Positional instability of basket during mapping and data analysis timestypically involves movement of shifting of the catheter basket.Different types of shifting include, but may not be limited to: rotationof the basket about its basket tip to anchor central axis; rotation ofthe basket about its axis normal to basket tip to anchor central axis; alinear shift of the basket along its catheter axis; a lateral shift ofindividual splines; and a combination thereof. As a result of shifting,some electrodes may come out of contact with endocardium, therebyproviding an inadequate or incomplete map and data analysis ofelectrical signals from the heart. The basket electrodes are the “frameof reference” for all the maps generated from the electrical signals.The maps are typically produced by the software are “with respect to thebasket electrode positions at the time the electrograms were recorded.”As an example, the map may tell the practitioner to ablate heart tissuemidway between, for example, Spline C, Electrode 5 and Spline D,Electrode 4. The practitioner will attempt to place an ablation catheterat this location, using the basket splines and electrodes as referencepoints. Any shift of the basket from its position at the time ofrecording to a different position at the time of ablation produceserrors (rotational or linear) or distortions in the maps. The magnitudesof these errors are proportional to amount of shift of the electrodes.Such errors or distortions are problematic to the practitioner.

Positional instability of basket during ablation is another area ofconcern for a practitioner. Electrogram maps will indicate to thepractitioner or clinician where to ablate “with respect to the splineand electrode positions at the time the map electrograms were recorded.”The practitioner or clinician must insert an ablation catheter betweensplines of mapping basket and direct its steerable tip to variouslocations on the endocardium, using the splines and electrodes of themapping basket as reference points within the heart. In order for theinformation on the electrogram maps to be useful, the spline andelectrode positions of the mapping basket during ablation must besubstantially equivalent to their positions during recording. Otherwise,practitioner or clinician will be relying on inaccurate referencelocations.

A lack of electrodes on the proximal spline segments of the mappingbasket is also a problematic for a practitioner or clinician. Mappingsoftware gathers timing data at discrete electrode positions (a “sparsedata array”) and calculates continuous interpolated timing results forall areas of the heart that reside within the electrode coverage area.The software cannot extrapolate results beyond the electrode coveragearea. Directed ablation is performed using the calculated, continuousinterpolated space-time maps, using the electrodes as reference points.There can be no mapping or useful directed ablation on areas of theheart outside of the area of electrode coverage. Basket catheters of theprior art generally have no electrodes on the proximal segments of theirbasket splines. Thus, with typical prior art devices, the proximalsegments of the atria (especially areas on the septal wall duringtranseptal mapping and ablation of the Left Atrium) cannot be mapped.Accordingly, these proximal wall segments of the atria cannot be ablatedby a practitioner or clinician with the directional control of maps orreference electrodes.

Furthermore, poor electrode contact in zones where electrodes existyields poor signal (atrial) to noise (ventricular) ratios. In the priorart devices, poor electrode contact results in decreased atrial signals(f-waves in atrial fibrillation and p-waves in sinus rhythm) as comparedto background noise (ventricular depolarizations). Such a poor signal tonoise ratio makes it difficult for software to automatically determineaccurate f-wave timing. This results in poor automatic mapping and theneed for trained human assistance in the recognition of f-waves.

A lack of electrode contact (no measurable atrial signals) is yetanother concern with devices of the prior art. Electrodes that aresufficiently displaced from the endocardial surface will record nomeasurable f-waves. This produces holes in the sparse data array andpoor resolution in zones of dropped data. While some interpolation ofthe missing data will occur with software, it will not be as accurate,since more widely spaced electrodes are used for such interpolation. Thedifference between poor electrode signal and no electrode signal isthat, in the former case, a human operator may be able to assist thesoftware algorithms in finding f-waves. However, in the latter case,there is nothing that the software or operator assistance can do toovercome the lack of available data.

RF noise may result from, among other things, a lack of shielding of thelong signal conduction wires that run from the mapping catheter to theassociated recorder. In a typical electrophysiology laboratory, thereare many other pieces of equipment that may generates significant RFnoise, which can be picked up by the long lengths of unshielded shieldedwires and superimposed upon the millivolt level signals from the mappingcatheter. Radiated noise is especially problematic when one attempts tocompensate for low amplitude atrial signals (due to poor electricalcontact) by increasing amplifier gain, because RF noise will beamplified along with the low amplitude signals.

Spline lateral bunching is also a concern with prior art devices. Withthe prior technology, multiple splines frequently “bunch up” (i.e.,gather together) due to varying atrial wall shapes. This often puts manyelectrodes in close proximity to each other, leaving large zones of theendocardium lacking in electrode coverage where the splines are not“bunched-up”. This will typically result in distortions in thecalculated maps, with zones of unnecessarily high resolution (with extrasplines and electrodes) adjacent to zones of poor resolution (lackingsplines and electrodes).

Prior art devices typically do not guard against electrode sliding(i.e., changing position) during heart contraction. The mapping softwaretypically assumes that the electrodes provide a signal from a singlelocation on the endocardium. If electrodes slide during heartcontraction, this assumption is violated. Fortunately, the valuableinformation for the detection of the f-wave during a-fib happens at thestart of contraction for any given electrode. Motion that occurs afterthis event is not likely to negatively impact the mapping.Unfortunately, electrodes are typically ganged together in groups ofeight on each spline. If one electrode starts to slide laterally duringthe contraction, it can (and will) drag the other seven electrodes onthe same spline with it. The impact on the resultant map will beproportional to the difference between the assumed position and actualposition of the electrode at the arrival of the f-wave, which isobviously problematic to a practitioner or clinician.

Poor spline/electrode identification under fluoroscopy is anotherconcern for the practitioner or clinician with the devices of the priorart. With prior art devices, the eight splines are typically identifiedsequentially with the letters A through H. The electrodes are identifiedwith the numbers one (most distal) to eight (most proximal). With priortechnology, each electrode operates as its own radiopaque marker. Thismay be convenient for locating individual electrodes. Additionally, anextra dummy electrode is often placed adjacent to an index electrode onseven out of eight splines. For the prior art device, the index“Spline/Electrodes” are A8, B7, C6, D5, E4, F3 and G2 electrodes. (H1 istypically not identified.) In principle, this scheme should allow theclinician to identify each spline and then each electrode. In reality,however, this system frequently produces ambiguous, difficult to resolvefluoroscopic images. As described above, the electrodes are thereference map by which the practitioner or clinician will ablate hearttissue. Difficulty in unambiguously identifying each spline and eachelectrode will result in uncertainty in ablation locations.

Poor performance of prior art devices in LA transeptal procedures is yetanother area of concern for the practitioner or clinician. It is muchmore difficult to achieve a high proportion of electrodes in highquality contact with the endocardium in the left atrium than it is inthe right atrium. The systems, devices and assemblies of the presentinvention offer improved electrode contact over the prior art in boththe left atrium and the right atrium.

Some non-limiting causes of problems are described below.

Positional instability of basket during mapping and data analysis timesmay be due to the lack of “all direction” counter-pressure. For theprior art device, pressure on distal half of a basket often produces anet compressive force on the splines that possesses a lateral component,pushing the distal end of the catheter out of touch with theendocardium. The only force counteracting this force is provided by thecatheter body shaft, which is free to float in the oversized inferiorvena cava (IVC). Counterforce of basket shaft, however, is unpredictableand unreliable. Further, basket electrode shapes (typically round) andradial forces (very light) often result in extremely tenuous basketanchoring to atrial walls. Very slight loads or torques will causebaskets of the prior art to shift position.

Positional instability of baskets of the prior art during ablation mayalso result from the tenuous anchoring of the basket to the endocardium,which results in movement of the basket during insertion andmanipulation of the ablation electrode. The practitioner or clinicianmust attempt to compensate for this motion by constantly repositioningthe basket or by using educated estimations of the locations of relevantsplines and electrodes at the time of mapping. This is complicated bythe lack of proximal wall electrodes in the prior art devices, i.e.,with the given shape of prior devices proximal electrodes would likelynot contact endocardium. Consequently, manufacturers have chosen toplace no electrodes on proximal segments of splines.

Poor electrode contact may result from misalignment of basket in atrialchamber; non-spherical atrial shape; basket/atrium size mismatch; lackof “all direction” counter pressure (causing distal electrodes towithdraw from endocardium as a result of heart contractions); inabilityof prior splines to track discontinuities in atrial wall curvatureand/or very light radial spline force preventing splines from conformingto local recesses in the atrial wall.

A lack of electrode contact often results from the same causes as “poorelectrode contact” and/or lack of proximal electrodes on splines.

RF noise results from the lack of RF shielding in catheter and extensioncables.

Spline lateral bunching may occur when splines expand againstendocardial surface. If that surface is at an oblique angle to the planeof the spline, a “side load” will be imparted on the spline. If thespline's lateral stiffness is too weak to resist this side load, then itwill deform in that direction. Further, certain spline and electrodeshapes (e.g., rectangular or substantially rectangular) are bettersuited to resist sideward sliding than other shapes (e.g., round).

For electrode sliding (i.e., changing position) during heartcontraction, the same effects that may result in spline lateral bunchingmay be exacerbated during heart contraction. As a result, the splinescan be forced to slide laterally (or twist helically) during systole.This spline movement (which carries the spline's electrodes) can produceimproper electrode position or motion artifacts in the electrograms.

Poor spline/electrode identification under fluoroscopy of prior artdevices is caused because each electrode acts as its own RO marker. Thislimits the possible schemes that one may employ to distinguish what areotherwise identical electrodes. Even if splines are definitivelyidentified at the location of their “index electrodes”, the splinesalways cross each other in the two dimensional fluoroscopic images. Itis frequently difficult or impossible to identify splines after thesecrossings. See FIG. 34I for an example of this phenomenon. It can bereadily appreciated in FIG. 34I that, if all electrodes appeared as asingle radiopaque marker, then it would be difficult to identify eachspline after such a crossing. However, by providing a distinguishablemarking scheme on adjacent splines (i.e., single electrode markersversus double electrode markers on adjacent splines), then it becomestrivial to accurately identify all portions of all splines.

With regard to poor performance of prior art devices in LA transeptalprocedure, a practitioner or clinician accesses the left atrium (LA)through a transeptal puncture. The practitioner or clinician pushes aspecially designed needle through the septal wall separating the rightatrium from the left atrium. The catheter guide sheath and mappingcatheter are then advanced through this puncture site, and the mappingcatheter deployed from this location. The transeptal puncture sitefrequently represents a very strong, misaligning constraint on thelocation of the proximal end of the basket. If not approximatelycentered in the left atrial chamber, this constraint can hold many(mostly proximal) electrodes off of the endocardium. If the transeptalpuncture site is not approximately centered with respect to the leftatrial chamber, the anchor portion of the basket will be drawn “offcenter” as well. This misalignment can have the effect of holding onesector of splines off of the proximal endocardium, while pushing theopposite sector into excess contact with its proximal endocardium.Currently, practitioners or clinicians attempt to compensate for thisproblem by using a “J tip” transeptal guide catheter, and directing theanchor portion of the catheter to a more centered location, or bydeflecting the portion of the catheter body that is proximal to theseptal wall puncture site.

The present inventions solves these problems of typical prior artdevices.

Improved positional stability of basket during mapping and data analysistimes is one area addressed by the present invention. First, poorsolutions and non-solutions include use of larger basket, whichfrequently exacerbates, rather than cures, the problem; the use ofinappropriate physical constraints on basket; the placing tip of basketinto one of the left pulmonary veins; using J tip guide catheter todeflect distal end of catheter body, which puts an angular, as well aslinear, deflection on anchor portion of basket; and/or advancing orretracting catheter body in an attempt to overcome or address theproblems of the prior art. The correct solutions, as identified by thepresent invention, include, but are not limited to, design basket shapeto fit atria; design basket shape to generate “all direction” counterpressure from its contact with endocardium; make basket slightlyoversized to diastolic size of atrium; allow basket to align itself toatrial shape; and/or relax all other constraints (as much as possible)and allow basket counter pressure to determine basket position; giveelectrodes and splines a shape (rounded rectangular) that isadvantageous to the spline anchoring itself to the endocardium withoutcausing trauma; and/or provide baskets in sufficiently small sizeincrements so that a size can be chosen that will be both stable andnon-traumatic.

To improve positional stability of basket during ablation, all of theposition stabilization techniques described above may be used.Experience has shown that, when all splines are poorly anchored, aslight force applied to one spline will move the entire basket. When thesplines are well anchored, however, slight pushing of one spline willdeflect only that one spline. The other splines will retain theirpositions and, when the side force is removed from the one spline, thesingle displaced spline will return to its former position.

The devices of the present invention provide proximal wall electrodesby, for example, adjusting electrode spacing or adding additionalelectrodes on each spline. Further, since new spline shape will putproximal spline segments into contact with endocardium, electrodesmounted in this location contribute to map.

Improved electrode contact may be achieved with the devices of thepresent invention by, for example, the practitioner's use of basketsthat are chosen to be slightly oversized to the patient's atrium. Theuse of an oversized basket will force the splines and the atrium toconform to the atrial shape will produce excellent electrode contact asthe endocardium deforms to conform to each other's shape, which willreduce bridging effects, giving better electrode contact. Additionaldesign elements that will improve electrode contact include, but are notlimited to, the incorporation of break points in spline, or theinclusion of assisting tension members (e.g., elastic bands) adjacent tothe splines, both said elements allowing short spline segment to flexindependently of each other, providing improved electrode to endocardiumcontact. Additional steps to improve electrogram signal quality include:the reduction of areas of electrode exposed to far field ventricular(i.e., noise) inputs but not near field atrial signal, which improvessignal to noise ratio; improved atria/basket size match by providingsmall increment basket sizes; and/or adding proximal curve to splineshapes allows severely distorted basket shapes that will matchnon-spherical atria, while being able to collapse into guide catheter.

The devices of the present invention may include RF noise shielding. AnRF shield incorporated into catheter and extension cable will reduceamplifier pick up of radiated noise. Moreover, excellent electrodecontact of the present invention will increase atrial signal magnitudeand reduce the need for high amplifier gain.

Reduced spline lateral bunching is achieved by the present invention bygiving the spline sufficient lateral stiffness to resist side loadsand/or using spline and electrodes shape (rectangular or substantiallyrectangular) better suited to taking purchase on the endocardial wallwhile still providing a non-traumatic anchor.

The present invention achieves reduce electrode sliding by, for example,improved positional stability of baskets, improved anchoring of splines,relaxation of inappropriate constraints.

Improving spline/electrode identification under fluoroscopy may beachieved by several aspects of the present invention. The basket designof the present invention produces a radio-transparent electrode.Separate means (radiopaque bands of metal or ink) may be varied fromspline to spline, or from electrode to electrode, to produce highlydistinguishable splines and electrodes, as seen in FIGS. 34G through34I. The system described here (one marker at every electrode on oddnumbered splines, two markers at every electrode on even numberedsplines, and four markers on each “index electrode”) produces anunambiguous fluoroscopic image.

For improved performance in LA transeptal procedure, it is desirablethat the selection of puncture site be more central to left atrialchamber. Further, a reduction of constraint of anchor imposed bytranseptal puncture site is also desirable.

Increased number of basket sizes by reducing step increment is also animportant aspect of the present invention. Many of the priortechnology's flaws are exacerbated by poor basket to atrium size match.Atria come in a continuum of sizes. The only way to achieve an adequatesize match while avoiding endocardial trauma is to offer a multitude ofbasket sizes in relatively small increments.

One method according to the present for sensing multiple local electricvoltages from endocardial surface of a heart, may comprise: providing asystem (10) for sensing multiple local electric voltages fromendocardial surface of a heart, comprising: a first elongate tubularmember (20) having a lumen (20C), a proximal end (20A) and a distal end(20B); a basket assembly (12) comprising: a plurality of flexiblesplines (14) for guiding a plurality of exposed electrodes (186), thesplines (14) having proximal portions (62), distal portions (66) andmedial portions (64) therein between, wherein the electrodes (186) aresubstantially flat electrodes and are substantially unidirectionallyoriented towards a direction outside of the basket assembly (12); aproximal anchor (18) for securably affixing the proximal portions (62)of the splines (14); said anchor (18) being secured at the distal end(20B) of the first elongate tubular member (20); a distal tip (16) forsecurably affixing the distal portions (66) of the splines (14), saidproximal anchor (18) and said distal tip (16) defining a longitudinalaxis (L) about which the splines (14) are disposed; wherein the splines(14) approach the distal tip (16) at an angle (α) of about 90° or lessthan about 90° as measured from a line segment between the proximalanchor (18) and the distal tip (16) along the longitudinal axis (L);wherein the splines (14) comprise a superelastic material such that thebasket assembly (12) exhibits a substantially cylindrical shape whenradially compressed and exhibits a radially expanded non-spherical shapewhen not radially compressed; and wherein each of the splines (14) inthe radially expanded non-spherical shape contain a proximal recurve(76) in the proximate portion (62) of the spline (14) at a location nearto the proximal anchor (18) of the basket assembly (12), the proximalrecurve (76) comprises a proximal excurvate outward bend (84) and aproximal incurvate inward bend (82) between said proximal excurvateoutward bend (84) and said proximal anchor (18), where an apex (83) ofthe proximal incurvate inward bend (82) is disposed in a directiontoward the distal tip (16) and is further disposed inwardly closertoward the distal tip (16) than the proximal excurvate outward bend(84); delivering the system (10) to the heart so that the basketassembly (12) is disposed within the right atrium of the heart;contacting proximal atrial tissue with the electrodes (186) disposed onthe proximal spline portions (62) to detect multiple local electricvoltages from endocardial surface thereat; and contacting atrial tissuewith the electrodes (186) disposed on the medial spline portions (64)and the distal spline portions (66) to detect multiple local electricvoltages from endocardial surface thereat. The splines (14) of thebasket assembly (12) may be flexible to match the contours of the rightatrium. Substantially all of the electrodes (186) may contact atrialtissue. Substantially all of the electrodes (186) may remainsubstantially spatially fixed with respect to atrial tissue. Asubstantial portion of atrial signals detected by the system (10) mayhave larger amplitudes than ventricular signals detected by the system(10). The splines (14) in the radially expanded non-spherical shape maycontain a distal excurvate outward bend (80) disposed at the distalportion (66) of the spline (14) at a location near to the distal tip(16) of the basket assembly (12) to bend the splines (14) back towardsthe proximal anchor (18); and wherein the splines (14) have a distalincurvate inward bend (78) between said distal tip (16) and said distalexcurvate outward bends (80). The splines (14) of the basket assembly(12) may be flexible to match the contours of the right atrium.

The devices of the present invention may suitably be used to detect ormap cardiac rhythm disorders. Details of methods for detecting ormapping cardiac rhythm disorders may be found in U.S. ProvisionalApplication No. 61/342,016, filed on Apr. 8, 2010, entitled “Methods,System And Apparatus For The Detection, Diagnosis And Treatment OfBiological Rhythm Disorders”, which published as U.S. Patent ApplicationPublication No. 2011/0251505 A1 for its corresponding Non-Provisionalapplication Ser. No. 13/081,411, the contents of all which areincorporated herein by reference.

The following aspects, embodiments, and the like are part of thedetailed description for the present invention. Embodiments directed todistal tip embodiments include, but are not limited to, as follows:

In one embodiment, a system (10) for sensing multiple local electricvoltages from endocardial surface of a heart is provided. The system maycomprise a first elongate tubular member (20) having a lumen (20C), aproximal end (20A) and a distal end (20B); and a basket assembly (12)comprising: a plurality of flexible splines (14) for guiding a pluralityof exposed electrodes (186), the splines (14) having proximal portions(62) and distal portions (66); an anchor (18) for securably affixing theproximal portions (62) of the splines (14); said anchor (18) beingsecured at the distal end (20B) of the first elongate tubular member(20); an encapsulated and filament-wrapped distal tip (16, 120)comprising an encapsulant (122) and a filament (124) for securablyaffixing the distal portions (66) of the splines (14) in a predeterminedangular relationship at said distal tip (16, 120); wherein the splines(14) comprise a superelastic material; and wherein the basket assembly(12) has a radially expanded non-cylindrical shape. The system (10) ofmay further comprise: a second elongate tubular member (46) having alumen (48), a proximal end (56) and a distal end (54); wherein thebasket assembly (12) is slidingly compressible to fit within the lumen(48) of the second elongate tubular member (46); wherein the basketassembly (12) has a substantially cylindrical shape when compressedwithin the lumen (48) of the second elongate tubular member (46); andwherein the basket assembly (12) has said radially expandednon-cylindrical shape when not compressed within the lumen (48) of thesecond elongate tubular member (46) and disposed past the distal end(54) of the second elongate tubular member (46). The encapsulant mayhave a smooth, non-thrombogenic outer surface free of voids and slotswhich would permit the passage or entry of blood thereinto. Theencapsulant (122) may comprise a thermoplastic material. The encapsulant(122) may also comprise a polyurethane material. The filament (124) maycomprise a polymeric filament, a metallic filament or combinationsthereof. The filament (124) may be laced, looped or wound between, overand under the splines (14) to substantially align and secure the distalportions (66) of the splines (14) in said predetermined angularrelationship. The flexible splines (14) may further comprise alignmentmembers (89) at the distal portions (66) of the splines (14); andwherein the filament (124) is also laced, looped or wound between, overand under the alignment members (89). The alignment members (89) maycomprise circular portions at the distal spline portions (66). Theangles (θ1-θ8) between said splines (14) at said distal tip (16, 120)forming said predetermined angular relationship may be all substantiallyequal to each other. Alternatively, at least one angle (θ1-θ8) betweensaid splines (14) at said distal tip (16, 120) forming saidpredetermined angular relationship may be different from another angle(θ1-θ8) between said splines (14) at said distal tip (16, 120). Whenbasket assembly (12) is in said radially expanded non-cylindrical shape,the splines (14) may extend beyond the distal tip (16, 120) and maycomprise excurvate bends (80) beyond the distal tip (16) to bend thesplines (14) back towards the anchor (18).

In one embodiment, a system (10) for sensing multiple local electricvoltages from endocardial surface of a heart, may comprise: a firstelongate tubular member (20) having a lumen (20C), a proximal end (20A)and a distal end (20B); and a basket assembly (12) comprising: aplurality of flexible splines (14) for guiding a plurality of exposedelectrodes (186), the splines (14) having proximal portions (62) anddistal portions (66); an anchor (18) for securably affixing the proximalportions (62) of the splines (14); said anchor (18) being secured at thedistal end (20B) of the first elongate tubular member (20); a distal tip(16, 150) comprising an elastomeric material for securably affixing thedistal portions of the splines (14) in a predetermined relationship atsaid distal tip (16, 150); wherein the splines (14) comprise asuperelastic material; and wherein the basket assembly (12) has aradially expanded non-cylindrical shape. The system may furthercomprise: a second elongate tubular member (46) having a lumen (48), aproximal end (56) and a distal end (54); wherein the basket assembly(12) is slidingly compressible to fit within the lumen (48) of thesecond elongate tubular member (46); wherein the basket assembly (12)has a substantially cylindrical shape when compressed within the lumen(48) of the second elongate tubular member (46); and wherein the basketassembly (12) has said radially expanded non-cylindrical shape when notcompressed within the lumen (48) of the second elongate tubular member(46) and disposed past the distal end (54) of the second elongatetubular member (46). The distal tip (16, 150) may have a smooth,non-thrombogenic outer surface free of voids and slots which wouldpermit the passage or entry of blood there into. Angles (θ1-θ8) betweensaid splines (14) at said distal tip (16, 150) forming saidpredetermined angular relationship may be all substantially equal toeach other. Alternatively, at least one angle (θ1-θ8) between saidsplines (14) at said distal tip (16, 150) forming said predeterminedangular relationship is different from another angle (θ1-θ8) betweensaid splines (14) at said distal tip (16, 150). The elastomeric materialmay comprise polyurethane, silicone and combinations thereof.

In one embodiment, a system (10) for sensing multiple local electricvoltages from endocardial surface of a heart, may comprise: a firstelongate tubular member (20) having a lumen (20C), a proximal end (20A)and a distal end (20B); a basket assembly (12) comprising: a pluralityof flexible splines (14) for guiding a plurality of exposed electrodes(186), the splines (14) having proximal portions (62) and distalportions (66); an anchor (18) for securably affixing the proximalportions (62) of the splines (14); said anchor (18) being secured at thedistal end (20B) of the first elongate tubular member (20); a distal tip(16, 150) comprising a flexible material for securably affixing thedistal portions of the splines (14); wherein the basket assembly (12)has a radially expanded non-cylindrical shape; wherein the splines (14)comprise a superelastic material; wherein said flexible materialcomprises a material selected from the group consisting of anelastomeric material, a non-elastic polymeric material, a thermoplasticmaterial and combinations thereof; and wherein the splines (14) approachthe tip (16) at an angle (α) of less than about 45° as measured from aline segment between the anchor (18) and the tip (16) along alongitudinal axis (L) between the proximal anchor (18) and the distaltip (16, 150). The system (10) of embodiment 19, may further comprise: asecond elongate tubular member (46) having a lumen (48), a proximal end(56) and a distal end (54); wherein the basket assembly (12) isslidingly compressible to fit within the lumen (48) of the secondelongate tubular member (46); wherein the basket assembly (12) has asubstantially cylindrical shape when compressed within the lumen (48) ofthe second elongate tubular member (46); and wherein the basket assembly(12) has said radially expanded non-cylindrical shape when notcompressed within the lumen (48) of the second elongate tubular member(46) and disposed past the distal end (54) of the second elongatetubular member (46). When basket assembly (12) is in said radiallyexpanded non-cylindrical shape, the splines (14) may extend beyond thedistal tip (16, 150) and may comprise excurvate bends (80) beyond thedistal tip (16) to bend the splines (14) back towards the anchor (18).The angles (θ1-θ8) between said splines (14) at said distal tip (16,150) forming said predetermined angular relationship may be allsubstantially equal to each other. Alternatively, at least one angle(θ1-θ8) between said splines (14) at said distal tip (16) forming saidpredetermined angular relationship may be different from another angle(θ1-θ8) between said splines (14) at said distal tip (16, 150).

In one embodiment, a system (10) for sensing multiple local electricvoltages from endocardial surface of a heart, may comprise: a firstelongate tubular member (20) having a lumen (20C), a proximal end (20A)and a distal end (20B); a basket assembly comprising: a plurality offlexible splines (14) for guiding a plurality of exposed electrodes(186), the splines (14) having proximal portions (62) and distalportions (66); an anchor (18) for securably affixing the proximalportions (62) of the splines (14); said anchor (18) being secured at thedistal end (20B) of the first elongate tubular member (20); a distal tip(16, 104, 104′, 126, 134, 140, 152) for comprising a first part and asecond part that are securably affixed to one and the other; wherein thedistal portions (66) of the splines (14) are securably and non-slidinglydisposed within said distal tip (16) in a predetermined angularrelationship; wherein the splines (14) approach the distal tip (16) atan angle (α) of about 90° or less than about 90° as measured from a linesegment between the anchor (18) and the tip (16) along the longitudinalaxis (L); wherein the basket assembly (12) has a radially expandednon-cylindrical shape; and wherein the splines (14) comprise asuperelastic material. The system (10) may further comprise: a secondelongate tubular member (46) having a lumen (48), a proximal end (56)and a distal end (54); wherein the basket assembly (12) is slidinglycompressible to fit within the lumen (48) of the second elongate tubularmember (46); wherein the basket assembly (12) has a substantiallycylindrical shape when compressed within the lumen (48) of the secondelongate tubular member (46); and wherein the basket assembly (12) hassaid radially expanded non-cylindrical shape when not compressed withinthe lumen (48) of the second elongate tubular member (46) and disposedpast the distal end (54) of the second elongate tubular member (46).Angles (θ1-θ8) between said splines (14) at said distal tip (16, 104,104′, 126, 134, 140, 152) forming said predetermined angularrelationship may be all substantially equal to each other.Alternatively, at least one angle (θ1-θ8) between said splines (14) atsaid distal tip (16) forming said predetermined angular relationship maybe different from another angle (θ1-θ8) between said splines (14) atsaid distal tip (16, 104, 104′, 126, 134, 140, 152). When basketassembly (12) is in said radially expanded non-cylindrical shape, thesplines (14) may extend beyond the distal tip (16, 104, 104′, 126, 134,140, 152) and may comprise excurvate bends (80) beyond the distal tip(16, 104, 104′, 126, 134, 140, 152) to bend the splines (14) backtowards the anchor (18). The splines (14) may have distal end portions(67); and further wherein the distal spline end portions (67) may besecurably and non-slidingly disposed within said distal tip (16, 104,104′, 126, 134, 140). The splines (14) may approach said distal tip (16)at an angle (α) of less than 45° as measured from a line segment betweensaid anchor (18) and said distal tip (16, 104, 104′, 126, 134, 140)along the longitudinal axis (L).

Embodiments directed to spline bends and recurves embodiments include,but are not limited to, as follows:

A system (10) for sensing multiple local electric voltages fromendocardial surface of a heart, may comprise: a first elongate tubularmember (20) having a lumen (20C), a proximal end (20A) and a distal end(20B); a basket assembly (12) comprising: a plurality of flexiblesplines (14) for guiding a plurality of exposed electrodes (186), thesplines (14) having proximal portions (62), distal portions (66) andmedial portions (64) therein between; a proximal anchor (18) forsecurably affixing the proximal portions (62) of the splines (14); saidproximal anchor (18) being secured at the distal end (20B) of the firstelongate tubular member (20); a distal tip (16) for securably affixingthe distal portions (66) of the splines (14), said proximal anchor (18)and said distal tip (16) defining a longitudinal axis (L) thereinbetween about which the splines (14) are disposed; wherein the splines(14) approach the distal tip (18) at an angle (α) of about 90° or lessthan about 90° as measured from a line segment between the proximalanchor (18) and the distal tip (16) along the longitudinal axis (L);wherein the splines (14) comprise a superelastic material such that thebasket assembly (12) exhibits a substantially cylindrical shape whenradially compressed and exhibits a radially expanded non-spherical shapewhen not radially compressed; and wherein at least some of the splines(14) in the radially expanded non-spherical shape contain a distalexcurvate outward bend (80) disposed at the distal portion (66) of thespline (14) at a location near to the distal tip (16) of the basketassembly (12) to bend the splines (14) back towards the proximal anchor(18). The system may further comprise: a second elongate tubular member(46) having a lumen (48), a proximal end (56) and a distal end (54);wherein the basket assembly (12) is slidingly compressible to fit withinthe lumen (48) of the second elongate tubular member (46); wherein thebasket assembly (12) has said substantially cylindrical shape whencompressed within the lumen (48) of the second elongate tubular member(46); and wherein the basket assembly (12) has said radially expandednon-spherical shape when not compressed within the lumen (48) of thesecond elongate tubular member (46) and disposed past the distal end(54) of the second elongate tubular member (46). When basket assembly(12) is in said radially expanded non-spherical shape, the splines (14)may extend beyond the distal tip (16); and, when basket assembly (14) isin said radially expanded non-spherical shape, apices (81) of the distalexcurvate bends (80) may be disposed beyond the distal tip (16). Thedistal spline portions (66) may be securably and non-slidingly disposedwithin said distal tip (16). The distal spline portions (66) may besecurably and non-slidingly disposed within said distal tip (16) in apredetermined angular relationship, wherein angles (θ1-θ8) between saidsplines (14) at said distal tip (16) forming said predetermined angularrelationship may be all substantially equal to each other; or wherein atleast one angle (θ1-θ8) between said splines (14) at said distal tip(16) forming said predetermined angular relationship may be differentfrom another angle (θ1-θ8) between said splines (14) at said distal tip(16). The splines (14) have distal end portions (67); and furtherwherein the distal spline end portions (67) may be securably andnon-slidingly disposed within said distal tip (16). The splines (14) mayapproach said distal tip (16) at an angle (α) of less than about 45° asmeasured from the line segment between said proximal anchor (18) andsaid distal tip (16) along the longitudinal axis (L). The splines (14)may have a distal incurvate inward bend (78) between said distal tip(16) and said distal excurvate outward bends (80). The distal tip (16)may have a non-thrombogenic outer surface free of voids and slots thatwould permit the passage or entry of blood thereinto. The splines (14)may have reduced widths at said distal portions (66) near the tip (16)as compared to spline widths at said medial portions (64).

A system (10) for sensing multiple local electric voltages fromendocardial surface of a heart, may comprise: a first elongate tubularmember (20) having a lumen (20C), a proximal end (20A) and a distal end(20B); a basket assembly (12) comprising: a plurality of flexiblesplines (14) for guiding a plurality of exposed electrodes (186), thesplines (14) having proximal portions (62), distal portions (66) andmedial portions (64) therein between; a proximal anchor (18) forsecurably affixing the proximal portions (62) of the splines (14); saidanchor (18) being secured at the distal end (20B) of the first elongatetubular member (20); a distal tip (16) for securably affixing the distalportions (66) of the splines (14), said proximal anchor (18) and saiddistal tip (16) defining a longitudinal axis (L) about which the splines(14) are disposed; wherein the splines (14) approach the distal tip (16)at an angle (α) of about 90° or less than about 90° as measured from aline segment between the proximal anchor (18) and the distal tip (16)along the longitudinal axis (L); wherein the splines (14) comprise asuperelastic material such that the basket assembly (12) exhibits asubstantially cylindrical shape when radially compressed and exhibits aradially expanded non-spherical shape when not radially compressed; andwherein each of the splines (14) in the radially expanded non-sphericalshape contain a proximal recurve (76) in the proximate portion (62) ofthe spline (14) at a location near to the proximal anchor (18) of thebasket assembly (12), the proximal recurve (76) comprises a proximalexcurvate outward bend (84) and a proximal incurvate inward bend (82)between said proximal excurvate outward bend (84) and said proximalanchor (18), where an apex (83) of the proximal incurvate inward bend(82) is disposed in a direction toward the distal tip (16) and isfurther disposed inwardly closer toward the distal tip (16) than theproximal excurvate outward bend (84). The system (10) may furthercomprise: a second elongate tubular member (46) having a lumen (48), aproximal end (56) and a distal end (54); wherein the basket assembly(12) is slidingly compressible to fit within the lumen (48) of thesecond elongate tubular member (46); wherein the basket assembly (12)has said substantially cylindrical shape when compressed within thelumen (48) of the second elongate tubular member (46); and wherein thebasket assembly (12) has said radially expanded non-spherical shape whennot compressed within the lumen (48) of the second elongate tubularmember (46) and disposed past the distal end (54) of the second elongatetubular member (46). The splines (14) may approach said distal tip (16)at an angle (α) of less than about 45° as measured from the line segmentbetween said proximal anchor (18) and said distal tip (16) along thelongitudinal axis (L). The splines (14) in the radially expandednon-spherical shape may contain a distal excurvate outward bend (80)disposed at the distal portion (66) of the spline (14) at a locationnear to the distal tip (16) of the basket assembly (12) to bend thesplines (14) back towards the proximal anchor (18); wherein the splines(14) may have a distal incurvate inward bend (78) between said distaltip (16) and said distal excurvate outward bends (80); and wherein, whenbasket assembly (12) is in said radially expanded non-spherical shape,the splines (14) may extend beyond the distal tip (16) and, when basketassembly (12) is in said radially expanded non-spherical shape, apices(81) of the distal excurvate bends (80) may be disposed beyond thedistal tip (16). The distal tip (16) may have a non-thrombogenic outersurface free of voids and slots that would permit the passage or entryof blood thereinto. The splines (14) may have reduced widths at saiddistal portions near the distal tip (16) as compared to spline widths atsaid medial portions (64). Each of the splines (14) have a lengthbetween said apex (83) of said proximal incurvate inward bend (82) andsaid proximal excurvate outward bend (84); and further wherein saidlength of at least one spline (14) may be different from said length ofanother of said splines (14). Alternatively, each of the splines (14)may have a substantially equal overall length between said proximalanchor (18) and said distal tip (16). Alternatively, each of the splines(14) may have a substantially equal overall length from said proximalanchor (18) and to said distal tip (16); and further wherein a lengthfrom said proximal excurvate outward bend (84) to said distal tip (16)for at least one of said splines (14) may be different from said lengthfor another one of said splines (14).

A system (10) for sensing multiple local electric voltages fromendocardial surface of a heart, may comprise: a first elongate tubularmember (20) having a lumen (20C), a proximal end (20A) and a distal end(20B); a basket assembly (12) comprising: a plurality of flexiblesplines (14) for guiding a plurality of exposed electrodes (186), thesplines (14) having proximal portions (62) and distal portions (66); aproximal anchor (18) for securably affixing the proximal portions (62)of the splines (14); said proximal anchor (18) being secured at thedistal end (20B) of the first elongate tubular member (20); a distal tip(16) for securably affixing the distal portions (66) of the splines(14), said proximal anchor (18) and said distal tip (16) defining alongitudinal axis (L) about which the splines (14) are disposed; whereinthe splines (14) approach the distal tip (16) at an angle (α) of lessthan about 45° as measured from a line segment between the proximalanchor (18) and the distal tip (16) along the longitudinal axis (L);wherein the splines (14) comprise a superelastic material such that thebasket assembly (12) exhibits a substantially cylindrical shape whenradially compressed and exhibits a radially expanded non-spherical shapewhen not radially compressed; wherein the splines (14) in the radiallyexpanded non-spherical shape contain a distal excurvate outward bend(80) disposed at the distal portion of the spline (14) at a locationnear to the distal tip (16) of the basket assembly (12) to bend thesplines (14) back towards the proximal anchor (18); wherein the splines(14) have a distal incurvate inward bend (78) between said distal tip(16) and said distal excurvate outward bends (80); wherein, when basketassembly (12) is in said radially expanded non-spherical shape, thesplines (14) extend beyond the distal tip (16) and, when basket assembly(12) is in said radially expanded non-spherical shape, apices (80) ofthe distal excurvate bends (80) are disposed beyond the distal tip (16);and wherein each of the splines (14) in the radially expandednon-spherical shape contain a proximal recurve (76) in the proximateportion (62) of the spline (14) at a location near to the proximalanchor (18) of the basket assembly (12), the proximal recurve (76)comprises a proximal excurvate outward bend (84) and a proximalincurvate inward bend (82) between said proximal excurvate outward bend(84) and said proximal anchor (18), where an apex (83) of the proximalincurvate inward bend (82) is disposed in a direction toward the distaltip (16) and is further disposed inwardly closer toward the distal tip(16) than the proximal excurvate outward bend (84). The system (10) mayfurther comprise: a second elongate tubular member (46) having a lumen(48), a proximal end (56) and a distal end (54); wherein the basketassembly (12) is slidingly compressible to fit within the lumen (48) ofthe second elongate tubular member (46); wherein the basket assembly(12) has said substantially cylindrical shape when compressed within thelumen (48) of the second elongate tubular member (46); and wherein thebasket assembly (12) has said radially expanded non-spherical shape whennot compressed within the lumen (48) of the second elongate tubularmember (46) and disposed past the distal end (54) of the second elongatetubular member (46). The distal spline portions (66) may be securablyand non-slidingly disposed within said distal tip (16). The splines (14)may have distal end portions (67); and further wherein the distal splineend portions (67) may be securably and non-slidingly disposed withinsaid distal tip (16). Each of the splines (14) may have a substantiallyequal overall length from said proximal anchor (18) and to said distaltip (16); and further wherein a length from said proximal excurvateoutward bend (84) to said distal tip (16) is for at least one of saidsplines (14) is different from said length for another one of saidsplines (14).

A system (10) for sensing multiple local electric voltages fromendocardial surface of a heart, may comprise: a first elongate tubular(20) member having a lumen (20C), a proximal end (20A) and a distal end(20B); a basket assembly (12) comprising: a plurality of flexiblesplines (14) for guiding a plurality of exposed electrodes (186), thesplines (14) having proximal portions (62) and distal portions (66); aproximal anchor (18) for securably affixing the proximal portions (62)of the splines (14); said proximal anchor (18) being secured at thedistal end (20B) of the first elongate tubular member (20); a distal tip(16) for securably affixing the distal portions (66) of the splines(14), said proximal anchor (18) and said tip (16) defining alongitudinal axis (L) about which the splines (14) are disposed; whereinthe splines (14) comprise a superelastic material such that the basketassembly (12) exhibits a substantially cylindrical shape when radiallycompressed and exhibits a radially expanded non-spherical shape when notradially compressed; wherein each of the splines (14) in the radiallyexpanded non-spherical shape contain a proximal recurve (76) in theproximate portion of the spline (14) at a location near to the anchor(18) of the basket assembly (12), the proximal recurve (76) comprises aproximal excurvate outward bend (84) and a proximal incurvate inwardbend (82) between said proximal excurvate outward bend (84) and saidproximal anchor (18), where an apex (83) of the proximal incurvateinward bend (82) is disposed in a direction toward the distal tip (16)and is further disposed inwardly closer toward the distal tip (16) thanthe proximal excurvate outward bend (84); and wherein the proximalincurvate inward bends (82) of some splines (14) have a differentgeometry from the proximal incurvate inward bends (82) of other splines(14); and wherein one or more tissue-contacting portions of theindividual splines (14) are of unequal length with respect to eachother, and each of the proximal incurvate inward bend portions (82) ofthe splines (14) possess compensating lengths such that the sum of thetissue facing portion plus proximal incurvate inward bend portion (82)of all splines (14) are substantially the same. The system (10) mayfurther comprise: a second elongate tubular member (46) having a lumen(48), a proximal end (56) and a distal end (54); wherein the basketassembly (12) is slidingly compressible to fit within the lumen (48) ofthe second elongate tubular member (46); wherein the basket assembly(12) has said substantially cylindrical shape when compressed within thelumen (48) of the second elongate tubular member (46); and wherein thebasket assembly (12) has said radially expanded non-spherical shape whennot compressed within the lumen (48) of the second elongate tubularmember (46) and disposed past the distal end (54) of the second elongatetubular member (46). The splines (14) may have distal end portions (67);and further wherein the distal spline end portions (67) may be securablyand non-slidingly disposed within said distal tip (16). The splines (14)in the radially expanded non-spherical shape may contain a distalexcurvate outward bend (80) disposed at the distal portion (66) of thespline (14) at a location near to the distal tip (16) of the basketassembly (12) to bend the splines (14) back towards the proximal anchor(18); wherein the splines (14) may have a distal incurvate inward bend(78) between said distal tip (16) and said distal excurvate outwardbends (80); and wherein, when basket assembly (12) is in said radiallyexpanded non-spherical shape, the splines (14) may extend beyond thedistal tip (16) and, when basket assembly (12) is in said radiallyexpanded non-spherical shape, apices (81) of the distal excurvate bends(80) are disposed beyond the distal tip (16).

Embodiments directed to spline assemblies for basket catheters include,but are not limited to, as follows:

A system (10) for sensing multiple local electric voltages fromendocardial surface of a heart, may comprise: an elongate tubular member(20) having a lumen (20C), a proximal end (20A) and a distal end (20B);a plurality of flexible splines (14) having proximal portions (62),distal portions (66) and medial portions (64) therein between, whereinthe splines (14) comprise an outer surface (190), an inner surface (192)and two side surfaces (194, 196); an anchor (18) for securably affixingthe proximal portions (62) of the splines (14), wherein the anchor (18)is securably affixed within the lumen (20C) of the elongate tubularmember (20) at the distal end (20B) of the elongate tubular member (20);a tip (16) for securably affixing the distal portions (66) of thesplines (14); and a polymeric member (185) comprising opposed a firstopen end (202) and a second open end (200) defining an open lumen (208)therein between and an inner member surface (208B) and an outer membersurface (208A), wherein at least one of the plurality of flexiblesplines (14) is at least partially disposed within the lumen (208) ofsaid polymeric member; a flexible electrode assembly strip (188) withone or more exposed electrodes (186) disposed on at least a portion ofthe outer surface (208A) of said polymeric member (185); wherein theflexible electrode assembly strip (188) comprises: a polymeric substrate(236) having an inner surface (236B) and an opposed outer surface(236A); said one or more exposed electrodes (186) disposed over at leastpart of the outer surface (236A) of the polymeric substrate (236); andone or more electrical traces (228) disposed over at least a portion ofthe inner surface (236B) of the polymeric substrate (236) or over atleast a portion of the outer surface (236A) of the polymeric substrate(236), said one or more electrical traces (228) being in electricalcommunication with said one or more exposed electrodes (186); wherein aportion of the flexible electrode assembly (188) transitions from theouter surface (208A) of said polymeric member (185) towards the innersurface (208B) of said polymeric member (185) prior to said anchor (18);and wherein another portion of the flexible electrode assembly (188)extends through at least a portion of said anchor (18) and into saidlumen (20C) of said elongate tubular member (20). The system (10) mayfurther comprise: a plurality of polymeric members (185) each comprisingsaid flexible electrode assembly strip (188); wherein each of saidplurality of flexible splines (14) are at least partially disposedwithin a different one of said plurality of polymeric members (185). Theone or more electrical traces (228) may be disposed over at least aportion of the inner surface (236B) of the polymeric substrate (236) andmay further comprise vias (230) to provide said electrical communicationbetween said one or more electrical traces (228) and said one or moreexposed electrodes (186). The one or more electrical traces (228) may bedisposed over at least a portion of the outer surface (236A) of thepolymeric substrate (236) and further comprising a polymeric covering(238, 240) over the outer surface (236A) of the polymeric substrate(236) and said electrical traces (228) with the one or more exposedelectrodes (186) being substantially free of the polymeric covering(238, 240). The first opposed open end (202) of the polymeric member(185) may be secured to the distal spline portion (66) of said at leastone of the plurality of flexible splines (14) at a position near to thedistal tip (16) and the second opposed open end (200) of the polymericmember (185) may be secured to the proximal spline portion (62) of saidat least one of the plurality of flexible splines (14) at a positionnear to the anchor (18). The first opposed open end (202) of thepolymeric member (185) may be sealingly secured to the distal splineportion (66) at the position near to the distal tip (16) by a seal(206). Medial portions of the polymeric member (185) between said firstopposed open end (202) and said second opposed open end (200) of thepolymeric member (185) may not be secured to said medial portions (64)of said at least one of the plurality of flexible splines (14). At leastone intermediate medial portion of the polymeric member (185) betweensaid first opposed open end (202) and said second opposed open end (200)of the polymeric member (185) may be secured to at least oneintermediate portion of said medial portions (64) of said at least oneof the plurality of flexible splines (14). The one or more exposedelectrodes (186) may comprise copper, gold, platinum, platinum black,platinum-iridium and combinations thereof. The outer surface (190) andthe inner surface (192) of said plurality of flexible splines (14) maybe substantially flat surfaces and the two side surfaces (194, 196) ofsaid plurality of flexible splines (14) may be convexly roundedsurfaces. The one or more exposed electrodes (186) may have asubstantially flat upper surface.

A system (10) for sensing multiple local electric voltages fromendocardial surface of a heart, may comprise: an elongate tubular member(20) having a lumen (20C), a proximal end (20A) and a distal end (20B);a plurality of flexible splines (14) having proximal portions (62),distal portions (66) and medial portions (64) therein between, whereinthe splines (14) comprise an outer surface (190), an inner surface (192)and two side surfaces (194. 196); an anchor (18) for securably affixingthe proximal portions (62) of the splines (14), wherein the anchor (18)is securably affixed within the lumen (20C) of the elongate tubularmember (20) at the distal end (20B) of the elongate tubular member (20);a tip (16) for securably affixing the distal portions (66) of thesplines (14); and a polymeric member (185) comprising opposed first(202) and second (200) open ends defining an open lumen (208) thereinbetween and an inner member surface (208B) and an outer member surface(208A), wherein at least one of the plurality of flexible splines (14)is at least partially disposed within the lumen (208) of said polymericmember (185); a flexible electrode assembly strip (188) with one or moreexposed electrodes (186) disposed on at least a portion of the outersurface (208A) of said polymeric member (185); wherein the flexibleelectrode assembly strip (188) comprises: a polymeric substrate (236)having an inner surface (236B) and an opposed outer surface (236A); saidone or more exposed electrodes (186) disposed over at least part of theouter surface (236A) of the polymeric substrate (236); and one or moreelectrical traces (228) disposed over at least a portion of the innersurface (236B) of the polymeric substrate (236) or over at least aportion of the outer surface (236A) of the polymeric substrate (236),said one or more electrical traces (228) being in electricalcommunication with said one or more exposed electrodes (186); whereinthe first opposed open end (202) of the polymeric member (185) issecured to the distal spline portion (66) of said at least one of theplurality of flexible splines (14) at a position near to the distal tip(16) and the second opposed open end (200) of the polymeric member (185)is secured to the proximal spline portion (62) of said at least one ofthe plurality of flexible splines (14) at a position near to the anchor(18); and wherein medial portions of the polymeric member (185) betweensaid first opposed open end (202) and said second opposed open end (200)of the polymeric member (185) are not secured to said medial portions(64) of said at least one of the plurality of flexible splines (14). Thesystem (10) may further comprise a seal (206) for sealingly engagingsaid first opposed open end (202) of the polymeric member (185) and saiddistal spline portion (66). A portion of the flexible electrode assembly(188) may extend through at least a portion of said anchor (18) and intosaid lumen (20C) of said elongate tubular member (20). The system (10)may further comprise: a plurality of polymeric members (185) eachcomprising said flexible electrode assembly strip (188); wherein each ofsaid plurality of flexible splines (14) may be at least partiallydisposed within a different one of said plurality of polymeric members(185). The one or more electrical traces (228) may be disposed over atleast a portion of the inner surface (236B) of the polymeric substrate(236) and may further comprise vias (230) to provide said electricalcommunication between said one or more electrical traces (228) and saidone or more exposed electrodes (186). The one or more electrical traces(228) may be disposed over at least a portion of the outer surface(236A) of the polymeric substrate (236) and may further comprise apolymeric covering (238, 240) over the outer surface (236A) of thepolymeric substrate (236) and said electrical traces (228) with the oneor more exposed electrodes (186) being substantially free of thepolymeric covering (238, 240). The one or more exposed electrodes (186)may comprise copper, gold, platinum, platinum black, platinum-iridiumand combinations thereof. The outer surface (190) and the inner surface(192) of said plurality of flexible splines (14) may be substantiallyflat surfaces and the two side surfaces (194, 196) of said plurality offlexible splines (14) may be convexly rounded surfaces. The one or moreexposed electrodes (186) have a substantially flat upper surface.

A system (10) for sensing multiple local electric voltages fromendocardial surface of a heart, may comprise: an elongate tubular member(20) having a lumen (20C), a proximal end (20A) and a distal end (20B);a plurality of flexible splines (14) having proximal portions (62),distal portions (66) and medial portions (64) therein between, whereinthe splines (14) comprise an outer surface (190), an inner surface (192)and two side surfaces (194, 196), wherein said inner and outer splinesurfaces (190, 192) have a substantially flat portion with thesubstantially flat portions being parallel to one and the other, andfurther wherein the two side spline surfaces (194, 196) are convexlyrounded to define a rounded-rectangular shape; an anchor (18) forsecurably affixing the proximal portions (62) of the splines (14),wherein the anchor (18) is securably affixed within the lumen (20C) ofthe elongate tubular member (20) at the distal end (20B) of the elongatetubular member (20); a tip (16) for securably affixing the distalportions (66) of the splines (14); and a plurality of polymeric members(185) each having opposed first (202) and second (200) open endsdefining an open lumen (208) therein between, wherein the polymericmembers (185) comprise an outer surface (208A), an inner surface (208B)and two side surfaces where a cross-sectional profile of the polymericmembers is elliptical to match a cross-sectional profile of therounded-rectangular shape of the splines (14) and is slightly largerthan the cross-sectional profile of the rounded-rectangular shape of thesplines (14) and wherein each of the plurality of flexible splines (14)is at least partially disposed within the lumen (208) of a different oneof said plurality of polymeric members (185); a flexible electrodeassembly strip (188) with one or more exposed electrodes (186) disposedon at least a portion of the outer surface (208A) of said polymericmembers (185); wherein the flexible electrode assembly strip (188)comprises: a polymeric substrate (236) having an inner surface (236B)and an opposed outer (236A) surface; said one or more exposed electrodes(186) disposed over at least part of the outer surface (236A) of thepolymeric substrate (236); and one or more electrical traces (228)disposed over at least a portion of the inner surface (236B) of thepolymeric substrate (236) or over at least a portion of the outersurface (236A) of the polymeric substrate (236), said one or moreelectrical traces (228) being in electrical communication with said oneor more exposed electrodes (186); wherein a portion of said e flexibleelectrode assembly strip (188) extends through at least a portion ofsaid anchor (18) and into said lumen (20C) of said elongate tubularmember (20). The one or more electrical traces (228) may be disposedover at least a portion of the inner surface (236B) of the polymericsubstrate (236) and may further comprise vias (230) to provide saidelectrical communication between said one or more electrical traces(228) and said one or more exposed electrodes (186). The one or moreelectrical traces (228) may be disposed over at least a portion of theouter surface (236A) of the polymeric substrate (236) and may furthercomprise a polymeric covering (238, 240) over the outer surface (236A)of the polymeric substrate (236) and said electrical traces (228) withthe one or more exposed electrodes (186) being substantially free of thepolymeric covering (238, 240). The first opposed open end (202) of thepolymeric member (185) may be sealingly secured to the distal splineportion (66) of said at least one of the plurality of flexible splines(14) at a position near to the distal tip (16) and the second opposedopen end (200) of the polymeric member (185) may be secured to theproximal spline portion (62) of said at least one of the plurality offlexible splines (14) at a position near to the anchor (18). Medialportions of the polymeric member between said first opposed open end(202) and said second opposed open end (200) of the polymeric member(185) may not be secured to said medial portions (64) of said at leastone of the plurality of flexible splines (14). At least one intermediatemedial portion of the polymeric member (185) between said first opposedopen end (202) and said second opposed open end (200) of the polymericmember (185) may be secured to at least one intermediate portion of saidmedial portions (64) of said at least one of the plurality of flexiblesplines (14). The one or more exposed electrodes (186) may comprisecopper, gold, platinum, platinum black, platinum-iridium andcombinations thereof. The one or more exposed electrodes (186) may havea substantially flat upper surface.

A system (10) for sensing multiple local electric voltages fromendocardial surface of a heart, may comprise: an elongate tubular member(20) having a lumen (20C), a proximal end (20A) and a distal end (20B);a plurality of flexible splines (14) having proximal portions (62),distal portions (66) and medial portions (64) therein between, whereinthe splines (14) comprise an outer surface (190), an inner surface (192)and two side surfaces (194, 196); an anchor (18) for securably affixingthe proximal portions (62) of the splines (14), wherein the anchor (18)is securably affixed within the lumen (20C) of the elongate tubularmember (20) at the distal end (20B) of the elongate tubular member (20);a tip (16) for securably affixing the distal portions (66) of thesplines (14); and a plurality of polymeric members (185) each havingopposed first (202) and second (200) open ends defining an open lumen(208) therein between and an outer surface (208A) and an inner surface(208B), wherein each of the plurality of flexible splines (14) is atleast partially disposed within the lumen (208) of a different one ofsaid plurality of polymeric members (185); a flexible electrode assemblystrip (188) with one or more exposed electrodes (186) disposed on atleast a portion of the outer surface (208A) of said polymeric members(185); wherein the flexible electrode assembly strip (188) comprises: apolymeric substrate (236) having an inner surface (236B) and an opposedouter surface (236A); said one or more exposed electrodes (186) disposedover at least part of the outer surface (236A) of the polymericsubstrate (236); and one or more electrical traces (228) disposed overat least a portion of the inner surface (236B) of the polymericsubstrate (236) or over at least a portion of the outer surface (236A)of the polymeric substrate (236), said one or more electrical traces(228) being in electrical communication with said one or more exposedelectrodes (186); wherein the flexible electrode assembly strip (188) iscompressed into the outer surface (208A) of the polymeric member (185);and wherein the flexible electrode assembly strip (188) is thermally oradhesively bonded to the outer surface (208A) of the polymeric member(185).

Embodiments directed to flex circuits and flexible electrode assembliesinclude, but are not limited to, as follows:

A device for insertion into a body lumen, may comprise: an electrodeassembly strip (188) with exposed electrodes (186) comprising: apolymeric substrate (236) having an upper surface (236A) and an opposedlower surface (236B); one or more electrodes (186) disposed over aportion of the upper surface (236A) of the polymeric substrate (236);one or more electrical traces (228) disposed over a portion of the lowersurface (236B) of the polymeric substrate (236) in electricalcommunication with the one or more electrodes (186) by way of metalplated holes (230) through the substrate (236); and a flexible polymericsubstrate (246) having a substrate surface (246A) and a substrate wall(246C); wherein the electrode assembly strip (188) is compressingly andthermally bonded to the substrate surface (246A) of the flexiblepolymeric substrate (246) to define a flexible electrode assembly strip(247); and wherein the electrode assembly strip (188) has a thicknessfrom about 0.0005 inches to about 0.008 inches. The electrode assemblystrip (188) may have a thickness from about 0.002 inches to about 0.004inches. The device may further comprise: a first polymeric covering(238) disposed portions of the substrate surface (236A) of the polymericsubstrate (236) not having the one or more electrodes (186) thereon,said first polymeric covering (238) having holes disposed over the oneor more electrodes (186) thereby defining one or more exposed electrodes(186); and a second polymeric covering (240) disposed over the one ormore electrical traces (228) and portions of the lower surface (236B) ofthe substrate (236) not having the one or more electrical traces (228)thereon. The polymeric substrate (236), the first polymeric covering(238) and the second polymeric covering (240) may comprise abiocompatible polyimide material. The flexible polymeric substrate (236)may comprise a biocompatible polyether block amide material. Theflexible polymeric substrate (236) may comprise a biocompatible polymerselected from the group consisting of polyesters, silicones, siliconerubbers, urethanes and combinations thereof. The flexible polymericsubstrate (236) may be a sheet. Alternatively, the flexible polymericsubstrate (236) may be an extruded tube having an open lumen.

A device for insertion into a body lumen, may comprise: an electrodeassembly strip (188) with exposed electrodes (186) comprising: apolymeric substrate (236) having an upper surface (236A) and an opposedlower surface (236B); at least two electrodes (186) disposed over aportion of the upper surface (236A) of the polymeric substrate (236); atleast two electrical traces (228) disposed over a portion of the lowersurface (236B) of the polymeric substrate (236) in electricalcommunication with the at least two electrodes by way of metal platedholes (230) through the substrate (236); a first polymeric covering(238) disposed portions of the upper surface (236A) of the polymericsubstrate (236) not having the at least two of said electrodes (186)thereon, said first polymeric covering (238) having holes disposed overthe at least two of said electrodes (186) thereby defining at least twoexposed electrodes (186); a second polymeric covering (240) disposedover the at least two of the electrical traces (228) and portions of thelower surface of the substrate not having the at least two electricaltraces (228) thereon; a first flexible polymeric tube (185) havingopposed open ends (200, 202) defining an open lumen (208) thereinbetween and an inner tubular surface (208B) and an outer tubular surface(208A); wherein the electrode assembly strip (188) is disposed over theouter surface (208A) of the first flexible polymeric tube (185); and asecond flexible polymeric tube (185) having opposed open ends (200, 202)defining an open lumen (208) therein between and an inner tubularsurface (208B) and an outer tubular surface (208A), wherein the secondflexible polymeric tube (185) is disposed over portions of the electrodeassembly strip (188) not having the exposed electrodes (186); whereinthe electrode assembly strip (188), the first flexible polymeric tube(185) and the second flexible polymeric tube (185) are compressingly andthermally bonded to each other to define a flexible electrode assemblystrip (247); and wherein the electrode assembly strip (188) has athickness from about 0.0005 inches to about 0.008 inches. The polymericsubstrate (236), the first polymeric covering (238) and the secondpolymeric covering (240) may comprise a biocompatible polyimidematerial. The first and second flexible polymeric tubes (185) maycomprise a polyether block amide material. The first flexible polymerictube (185) may be an extruded tube. The flexible electrode assemblystrip (247) may have a substantially smooth and atraumatic overall outersurface (246A). The device may further comprise: an elongate tubularmember (20) having a lumen (20C), a proximal end (20A) and a distal end(20B); a plurality of flexible splines (14) having proximal portions(62), distal portions (66) and medial portions (64) therein between,wherein the splines (14) comprise an outer surface (190), an innersurface (192) and two side surfaces (194, 196); an anchor (18) forsecurably affixing the proximal portions (62) of the splines (14),wherein the anchor (18) is securably affixed within the lumen (20C) ofthe elongate tubular member (20) at the distal end (20B) of the elongatetubular member (20); and a tip (16) for securably affixing the distalportions (66) of the splines (14); wherein the flexible electrodeassembly strip (247) is disposed over at least one of the plurality ofsplines (14). The device may further comprise a plurality of flexibleelectrode assembly strips (247), wherein each of said plurality ofsplines (14) has at least one of said plurality of flexible electrodeassembly strips (247) disposed there over.

A device for insertion into a body lumen, may comprise: an electrodeassembly strip (188) with exposed electrodes (186) comprising: apolymeric substrate (236) having an upper surface (236A) and an opposedlower surface (236B); one or more of substantially flat electrodes (186)disposed over a portion of the upper surface (236A) of the polymericsubstrate (236); one or more of electrical traces (228) disposed over aportion of the lower surface (236B) of the polymeric substrate (236) inelectrical communication with the one or more electrodes (186) by way ofmetal plated holes (230) through the substrate (236); a first polymericcovering (238) disposed portions of the upper surface (236A) of thepolymeric substrate (236) not having the one or more of the electrodes(186) thereon, said first polymeric covering (238) having holes disposedover the one or more electrodes (186) thereby defining one or moreexposed electrodes (186); a second polymeric covering (240) disposedover the over the one or more electrical traces (228) and portions ofthe lower surface (236B) of the substrate (236) not having the one ormore electrical traces (228) thereon; and a flexible polymeric tube(185) having opposed open ends (200, 202) defining an open lumen (208)therein between and an inner tubular surface (208B) and an outer tubularsurface (208A) defining a tubular wall (210) therein between; whereinthe electrode assembly strip (188) is compressingly and thermally bondedto the outer surface (208A) of the flexible polymeric tube (185) todefine a flexible electrode assembly strip (247); wherein substantialportions of the substantially flat electrodes (186) remain substantiallyflat to provide substantially flat exposed electrodes (186); and whereinthe electrode assembly strip (188) has a thickness from 0.0005 inches toabout 0.008 inches. The polymeric substrate (236) may comprise apolyimide material. The first polymeric covering (238) and the secondpolymeric covering (240) may comprise a polyimide material. The flexiblepolymeric tube (185) may comprise a polyether block amide material. Theflexible polymeric tube (185) may be an extruded tube. The electrodeassembly strip (188) may be compressed into the tubular wall (210) ofthe flexible polymeric tube (185) to provide a substantially smooth andatraumatic overall outer surface for the flexible electrode assemblystrip. The device may further comprise: an elongate tubular member (20)having a lumen (20C), a proximal end (20A) and a distal end (20B); oneor more flexible splines (14) having proximal portions (62), distalportions (66) and medial portions (64) therein between, wherein the oneor more splines (14) comprise an outer surface (190), an inner surface(192) and two side surfaces (194, 196); an anchor (18) for securablyaffixing the proximal portions (62) of the one or more splines (14),wherein the anchor (18) is securably affixed within the lumen (20C) ofthe elongate tubular member (20) at the distal end (20B) of the elongatetubular member (20); and a tip (16) for securably affixing the distalportions (66) of the one or more splines (14); wherein the flexibleelectrode assembly strip (247) is disposed over at least one of the oneor more splines (14). The device may further comprise one or more offlexible electrode assembly strips (247), wherein each of said one ormore of the splines (14) may have at least one of said one or more ofthe flexible electrode assembly strips (247) disposed there over.

A device for insertion into a body lumen, may comprise an electrodeassembly strip (188) with exposed electrodes (186) comprising: apolymeric substrate (236) having an upper surface (236A) and an opposedlower surface (236B); at least two substantially flat electrodes (186)disposed over a portion of the upper surface (236A) of the polymericsubstrate (236); at least two electrical traces (228) disposed over aportion of the lower surface (236B) of the polymeric substrate (236) inelectrical communication with the at least two electrodes (186) by wayof metal plated holes (230) through the substrate (236); a firstpolymeric covering (238) disposed portions of the upper surface (236A)of the polymeric substrate (236) not having the at least two of saidelectrodes (186) thereon, said first polymeric covering (238) havingholes disposed over the at least two of said electrodes (186) therebydefining at least two exposed electrodes (186); a second polymericcovering (240) disposed over the over the plurality of electrical traces(228) and portions of the lower surface (236B) of the substrate (236)not having electrical traces (228) thereon; a first flexible polymerictube (185) having opposed open ends (200, 202) defining an open lumen(208) therein between and an inner tubular surface (208B) and an outertubular surface (208A); wherein the electrode assembly strip (188) isdisposed over the outer surface (208A) of the first flexible polymerictube (185); and a second flexible polymeric tube (185) having opposedopen ends (200, 202) defining an open lumen (208) therein between and aninner tubular surface (208B) and an outer tubular surface (208A),wherein the second flexible polymeric tube (185) is disposes overportions of the electrode assembly strip (188) not having the exposedelectrodes (186), wherein the electrode assembly strip (186), the firstflexible polymeric tube (185) and the second flexible polymeric tube(185) are compressingly and thermally bonded to each other to define aflexible electrode assembly strip (247); wherein substantial portions ofthe at least two substantially flat electrodes (186) remainsubstantially flat to provide at least two substantially flat exposedelectrodes (186); and wherein the electrode assembly strip (188) has athickness from about 0.0005 inches to about 0.008 inches. The polymericsubstrate (236) may comprise a polyimide material. The first polymericcovering (238) and the second polymeric covering (240) may comprise apolyimide material. The first and second flexible polymeric tubes (185)may comprise a polyether block amide material. The first flexiblepolymeric tube (185) may be an extruded tube. The flexible electrodeassembly strip (247) may have a substantially smooth and atraumaticoverall outer surface. The device may further comprise: an elongatetubular member (20) having a lumen (20C), a proximal end (20A) and adistal end (20B); one or more flexible splines (14) having proximalportions (62), distal portions (66) and medial portions (64) thereinbetween, wherein the splines (14) comprise an outer surface (190), aninner surface (192) and two side surfaces (194, 196); an anchor (18) forsecurably affixing the proximal portions (62) of the splines (14),wherein the anchor (18) is securably affixed within the lumen (20C) ofthe elongate tubular member (20) at the distal end (20B) of the elongatetubular member (20); and a tip (16) for securably affixing the distalportions (66) of the one or more splines (14); wherein the flexibleelectrode assembly strip (247) is disposed over at least one of the oneor more of the splines (14).

Embodiments directed to methods for sensing multiple local electricvoltages from endocardial surface of a heart include, but are notlimited to, as follows:

A method for sensing multiple local electric voltages from endocardialsurface of a heart, may comprise: providing a system (10) for sensingmultiple local electric voltages from endocardial surface of a heart,comprising: a first elongate tubular member (20) having a lumen (20C), aproximal end (20A) and a distal end (20B); a basket assembly (12)comprising: a plurality of flexible splines (14) for guiding a pluralityof exposed electrodes (186), the splines (14) having proximal portions(62), distal portions (66) and medial portions (64) therein between,wherein the electrodes (186) are substantially flat electrodes and aresubstantially unidirectionally oriented towards a direction outside ofthe basket assembly (12); a proximal anchor (18) for securably affixingthe proximal portions (62) of the splines (14); said anchor (18) beingsecured at the distal end (20B) of the first elongate tubular member(20); a distal tip (16) for securably affixing the distal portions (66)of the splines (14), said proximal anchor (18) and said distal tip (16)defining a longitudinal axis (L) about which the splines (14) aredisposed; wherein the splines (14) approach the distal tip (16) at anangle (α) of about 90° or less than about 90° as measured from a linesegment between the proximal anchor (18) and the distal tip (16) alongthe longitudinal axis (L); wherein the splines (14) comprise asuperelastic material such that the basket assembly (12) exhibits asubstantially cylindrical shape when radially compressed and exhibits aradially expanded non-spherical shape when not radially compressed; andwherein each of the splines (14) in the radially expanded non-sphericalshape contain a proximal recurve (76) in the proximate portion (62) ofthe spline (14) at a location near to the proximal anchor (18) of thebasket assembly (12), the proximal recurve (76) comprises a proximalexcurvate outward bend (84) and a proximal incurvate inward bend (82)between said proximal excurvate outward bend (84) and said proximalanchor (18), where an apex (83) of the proximal incurvate inward bend(82) is disposed in a direction toward the distal tip (16) and isfurther disposed inwardly closer toward the distal tip (16) than theproximal excurvate outward bend (84); delivering the system (10) to theheart so that the basket assembly (12) is disposed within the rightatrium of the heart; contacting proximal atrial tissue with theelectrodes (186) disposed on the proximal spline portions (62) to detectmultiple local electric voltages from endocardial surface thereat; andcontacting atrial tissue with the electrodes (186) disposed on themedial spline portions (64) and the distal spline portions (66) todetect multiple local electric voltages from endocardial surfacethereat. The splines (14) of the basket assembly (12) may be flexible tomatch the contours of the right atrium. Substantially all of theelectrodes (186) may contact atrial tissue. Substantially all of theelectrodes (186) may remain substantially spatially fixed with respectto atrial tissue. A substantial portion of atrial signals detected bythe system (10) may have larger amplitudes than ventricular signalsdetected by the system (10). The splines (14) in the radially expandednon-spherical shape may contain a distal excurvate outward bend (80)disposed at the distal portion (66) of the spline (14) at a locationnear to the distal tip (16) of the basket assembly (12) to bend thesplines (14) back towards the proximal anchor (18); and wherein thesplines (14) have a distal incurvate inward bend (78) between saiddistal tip (16) and said distal excurvate outward bends (80). Thesplines (14) of the basket assembly (12) may be flexible to match thecontours of the right atrium.

While various embodiments of the present invention are specificallyillustrated and/or described herein, it will be appreciated thatmodifications and variations of the present invention may be effected bythose skilled in the art without departing from the spirit and intendedscope of the invention. Further, any of the embodiments or aspects ofthe invention as described in the claims or in the specification may beused with one and another without limitation.

1.-10. (canceled)
 11. A method for sensing multiple local electricvoltages from endocardial surface of a heart and minimizingelectro-magnetic interference, comprising: providing a system forsensing multiple local electric voltages from endocardial surface of aheart, comprising: a first elongate tubular member having a lumen, aproximal end and a distal end; a basket assembly comprising: a pluralityof flexible splines for guiding a plurality of exposed electrodes, thesplines having proximal portions, distal portions and medial portionstherein between, wherein the exposed electrodes are substantially flatelectrodes and are substantially unidirectionally oriented towards adirection outside of the basket; a proximal anchor for securablyaffixing the proximal portions of the splines; said proximal anchorbeing secured at the distal end of the first elongate tubular member; adistal tip for only securably affixing the distal portions of thesplines, said proximal anchor and said distal tip defining alongitudinal axis therein between about which the splines are disposed;and a second elongate tubular member having a lumen, a proximal end anda distal end, the second elongate tubular member having a braided shielddisposed between the proximal end of the second elongate tubular memberand the distal end of the second elongate tubular member to minimizeelectro-magnetic interference from sources outside of the secondelongate tubular member; wherein the basket assembly is slidinglycompressible within the lumen of the second elongate tubular member;wherein the splines comprise a superelastic material such that thebasket assembly exhibits a substantially cylindrical shape when radiallycompressed within the second elongate tubular member and exhibits aradially expanded non-spherical shape when not radially compressedwithin the second elongate tubular member; delivering the system to theheart; sliding the basket assembly beyond the distal end of the secondelongate tubular member, whereby the splines radially expand into theradially expanded non-spherical shape to dispose the basket assemblywithin a chamber of the heart; contacting proximal heart tissue withinthe chamber of the heart with the substantially all of exposedelectrodes disposed on the proximal spline portions; detecting multiplelocal electric voltages with the exposed electrodes contacting theproximal heart tissue from endocardial surface thereat; contacting otherheart tissue within the chamber of the heart with substantially all ofthe exposed electrodes disposed on the medial spline portions and thedistal spline portions; detecting multiple local electric voltages withthe exposed electrodes disposed on the medial spline portions and thedistal spline portions contacting the other heart tissue fromendocardial surface thereat; and minimizing electro-magneticinterference from sources outside of the second elongate tubular member.12. The method of claim 11, wherein the multiple local electric voltagesform an electrocardiogram having a P wave, a QRS complex and a T wave.13. The method of claim 11, wherein the splines approach the distal tipat an angle of about 90° or less than about 90° as measured from a linesegment between the proximal anchor and the distal tip along thelongitudinal axis.
 14. The method of claim 11, wherein each of thesplines in the radially expanded non-spherical shape contain a proximalrecurve in the proximate portion of the spline at a location near to theproximal anchor of the basket assembly, the proximal recurve comprises aproximal excurvate outward bend and a proximal incurvate inward bendbetween said proximal excurvate outward bend and said proximal anchor,where an apex of the proximal incurvate inward bend is disposed in adirection toward the distal tip and is further disposed inwardly closertoward the distal tip than the proximal excurvate outward bend.
 15. Themethod of claim 11, wherein the splines in the radially expandednon-spherical shape contain an distal excurvate outward bend disposed atthe distal portion of the spline at a location near to the distal tip ofthe basket assembly to bend the splines back towards the proximalanchor; and wherein the splines have a distal incurvate inward bendbetween said distal tip and said distal excurvate outward bends.
 16. Themethod of claim 11, wherein, when the basket assembly is in saidradially expanded non-spherical shape, the splines extend beyond thedistal tip and apices of the distal excurvate bends are disposed beyondthe distal tip.
 17. The method of claim 11, wherein the distal tipconsisting essentially of means for only securably affixing the distalportions of the splines.
 18. The method of claim 11, wherein the splinesof the basket assembly are flexible and wherein the method furthercomprises: matching contours of the chamber with the splines of thebasket assembly.
 19. The method of claim 11, wherein the splines of thebasket assembly are flexible; wherein the chamber of the heart is anatrium of the heart; and wherein the method further comprises: matchingcontours of the atrium with the splines of the basket assembly.
 20. Themethod of claim 19, further comprising: spatially fixing substantiallyall of the exposed electrodes with respect to the proximal atrial tissueand the other atrial tissue.
 21. The method of claim 11, furthercomprising: minimizing exposure of the exposed electrodes to ventricularsignals whereby a substantial portion of atrial signals detected by thesystem have larger amplitudes than ventricular signals detected by thesystem.
 22. The method of claim 11, wherein the exposed electrodes areselected from the group consisting of copper electrodes, goldelectrodes, platinum electrodes, platinum black electrodes,platinum-iridium electrodes and combinations thereof.
 23. The method ofclaim 11, further comprising: recording the multiple local electricvoltages.
 24. A method for sensing multiple local electric voltages fromendocardial surface of a heart with fluoroscopic imaging, comprising:providing a system for sensing multiple local electric voltages fromendocardial surface of a heart, comprising: a first elongate tubularmember having a lumen, a proximal end and a distal end; a basketassembly comprising: a plurality of flexible splines for guiding aplurality of exposed radio-transparent electrodes, the splines havingproximal portions, distal portions and medial portions therein between,wherein the exposed electrodes are substantially flat electrodes and aresubstantially unidirectionally oriented towards a direction outside ofthe basket; a plurality of radiopaque markers where at least oneradiopaque marker is disposed on each of said plurality of flexiblesplines at a location near and below at least one of said plurality ofexposed electrodes; a proximal anchor for securably affixing theproximal portions of the splines; said proximal anchor being secured atthe distal end of the first elongate tubular member; a distal tip foronly securably affixing the distal portions of the splines, saidproximal anchor and said distal tip defining a longitudinal axis thereinbetween about which the splines are disposed; and a second elongatetubular member having a lumen, a proximal end and a distal end; whereinthe basket assembly is slidingly compressible within the lumen of thesecond elongate tubular member; wherein the splines comprise asuperelastic material such that the basket assembly exhibits asubstantially cylindrical shape when radially compressed within thesecond elongate tubular member and exhibits a radially expandednon-spherical shape when not radially compressed within the secondelongate tubular member; delivering the system to the heart; sliding thebasket assembly beyond the distal end of the second elongate tubularmember, whereby the splines radially expand into the radially expandednon-spherical shape to dispose the basket assembly within a chamber ofthe heart; contacting proximal heart tissue within the chamber of theheart with the substantially all of exposed electrodes disposed on theproximal spline portions; observing the plurality of radiopaque markersunder flurorscopy; detecting multiple local electric voltages with theexposed electrodes contacting the proximal heart tissue from endocardialsurface thereat; contacting other heart tissue within the chamber of theheart with substantially all of the exposed electrodes disposed on themedial spline portions and the distal spline portions; detectingmultiple local electric voltages with the exposed electrodes disposed onthe medial spline portions and the distal spline portions contacting theother heart tissue from endocardial surface thereat.
 25. The method ofclaim 24, wherein at least one radiopaque marker is disposed on each ofsaid plurality of flexible splines at a location near and below each ofsaid plurality of exposed electrodes.
 26. The method of claim 24,wherein the multiple local electric voltages form an electrocardiogramhaving a P wave, a QRS complex and a T wave.
 27. The method of claim 24,wherein the splines approach the distal tip at an angle of about 90° orless than about 90° as measured from a line segment between the proximalanchor and the distal tip along the longitudinal axis.
 28. The method ofclaim 24, wherein each of the splines in the radially expandednon-spherical shape contain a proximal recurve in the proximate portionof the spline at a location near to the proximal anchor of the basketassembly, the proximal recurve comprises a proximal excurvate outwardbend and a proximal incurvate inward bend between said proximalexcurvate outward bend and said proximal anchor, where an apex of theproximal incurvate inward bend is disposed in a direction toward thedistal tip and is further disposed inwardly closer toward the distal tipthan the proximal excurvate outward bend.
 29. The method of claim 24,wherein the splines in the radially expanded non-spherical shape containan distal excurvate outward bend disposed at the distal portion of thespline at a location near to the distal tip of the basket assembly tobend the splines back towards the proximal anchor; and wherein thesplines have a distal incurvate inward bend between said distal tip andsaid distal excurvate outward bends.
 30. The method of claim 24,wherein, when the basket assembly is in said radially expandednon-spherical shape, the splines extend beyond the distal tip and apicesof the distal excurvate bends are disposed beyond the distal tip. 31.The method of claim 24, wherein the distal tip consisting essentially ofmeans for only securably affixing the distal portions of the splines.32. The method of claim 24, wherein the splines of the basket assemblyare flexible and wherein the method further comprises: matching contoursof the chamber with the splines of the basket assembly.
 33. The methodof claim 24, wherein the splines of the basket assembly are flexible;wherein the chamber of the heart is an atrium of the heart; and whereinthe method further comprises: matching contours of the atrium with thesplines of the basket assembly.
 34. The method of claim 33, furthercomprising: spatially fixing substantially all of the exposed electrodeswith respect to the proximal atrial tissue and the other atrial tissue.35. The method of claim 24, further comprising: minimizing exposure ofthe exposed electrodes to ventricular signals whereby a substantialportion of atrial signals detected by the system have larger amplitudesthan ventricular signals detected by the system.
 36. The method of claim24, wherein the exposed electrodes are selected from the groupconsisting of copper electrodes, gold electrodes, platinum electrodes,platinum black electrodes, platinum-iridium electrodes and combinationsthereof.
 37. The method of claim 24, further comprising: recording themultiple local electric voltages.